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annotate lwbasic/parser.c @ 56:337301ddf74a

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Fixed error with pragma and *pragma directives
author lost@l-w.ca
date Wed, 06 Apr 2011 00:12:01 -0600
parents 5325b640424d
children
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1 /*
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2 compiler.c
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3
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4 Copyright © 2011 William Astle
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5
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6 This file is part of LWTOOLS.
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7
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8 LWTOOLS is free software: you can redistribute it and/or modify it under the
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9 terms of the GNU General Public License as published by the Free Software
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10 Foundation, either version 3 of the License, or (at your option) any later
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11 version.
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12
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13 This program is distributed in the hope that it will be useful, but WITHOUT
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14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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16 more details.
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17
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18 You should have received a copy of the GNU General Public License along with
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19 this program. If not, see <http://www.gnu.org/licenses/>.
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20 */
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21
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22 /*
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23 This is the actual compiler bit; it drives the parser and code generation
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24 */
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25
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26 #include <stdio.h>
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27
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28 #include <lw_alloc.h>
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29 #include <lw_string.h>
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30
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31 #include "lwbasic.h"
32
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32 #include "symtab.h"
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33
34
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34 static void expect(cstate *state, int tt)
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35 {
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36 if (state -> lexer_token != tt)
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37 lwb_error("Expecting %s, got %s\n", lexer_token_name(tt), lexer_return_token(state));
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38 lexer(state);
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39 }
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40
32
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41
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42 /* size of a type */
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43 static int sizeof_type(int type)
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44 {
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45 /* everything is an "int" right now; 2 bytes */
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46 return 2;
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47 }
25
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48
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49 /* parse a type; the next token will be acquired as a result */
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50 /* the token advancement is to provide consistency */
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51 static int parse_type(cstate *state)
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52 {
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53 int pt = -1;
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54
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55 switch (state -> lexer_token)
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56 {
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57 case token_kw_integer:
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58 pt = 1;
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59 break;
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60
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61 default:
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62 lwb_error("Invalid type specification");
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63 }
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64 lexer(state);
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65 /* look for "unsigned" modifier for integer types */
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66 return pt;
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67 }
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68
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69 static void parse_expr(cstate *state, int prec);
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70 static void parse_term(cstate *state);
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71 static int parse_expression(cstate *state)
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72 {
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73 state -> expression = 1;
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74
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75 parse_expr(state, 0);
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76
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77 state -> expression = 0;
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78 return 1;
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79 }
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80
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81 static void parse_decls(cstate *state)
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82 {
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83 /* declarations */
33
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84 /* the first thing that doesn't look like a declaration is assumed */
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85 /* to be a statement and will trigger a bailout */
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86 int vt;
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87 char *vn;
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88 symtab_entry_t *se;
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89
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90 for (;;)
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91 {
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92 switch (state -> lexer_token)
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93 {
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94 /* DIM keyword */
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95 case token_kw_dim:
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96 lexer(state);
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97 if (state -> lexer_token != token_identifier)
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98 {
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99 lwb_error("Expecting identifier, got %s\n", lexer_return_token(state));
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100 }
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101 vn = lw_strdup(state -> lexer_token_string);
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102 lexer(state);
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103 if (state -> lexer_token != token_kw_as)
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104 {
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105 lwb_error("Expecting AS, got %s\n", lexer_return_token(state));
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106 }
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107 lexer(state);
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108 vt = parse_type(state);
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109
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110 se = symtab_find(state -> local_syms, vn);
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111 if (se)
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112 {
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113 lwb_error("Multiply defined local variable %s", vn);
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114 }
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115 state -> framesize += sizeof_type(vt);
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116 symtab_register(state -> local_syms, vn, -(state -> framesize), symtype_var, NULL);
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117
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118 lw_free(vn);
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119 break;
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120
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121 /* blank lines allowed */
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122 case token_eol:
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123 break;
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124
33
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125 default:
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126 return;
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127 }
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128 if (state -> lexer_token != token_eol)
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129 lwb_error("Expecting end of line; got %s\n", lexer_return_token(state));
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130 lexer(state);
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131 }
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132 }
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133
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134 static void parse_statements(cstate *state)
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135 {
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136 symtab_entry_t *se;
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137 int et;
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138
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139 for (;;)
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140 {
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141 switch (state -> lexer_token)
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142 {
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143 /* blank lines allowed */
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144 case token_eol:
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145 break;
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146
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147 /* variable assignment */
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148 case token_identifier:
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149 se = symtab_find(state -> local_syms, state -> lexer_token_string);
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150 if (!se)
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151 {
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152 se = symtab_find(state -> global_syms, state -> lexer_token_string);
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153 }
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154 if (!se)
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155 lwb_error("Unknown variable %s\n", state -> lexer_token_string);
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156 lexer(state);
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157 /* ensure the first token of the expression will be parsed correctly */
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158 state -> expression = 1;
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159 expect(state, token_op_assignment);
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160
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161 /* parse the expression */
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162 et = parse_expression(state);
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163
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164 /* check type compatibility */
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165
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166 /* actually do the assignment */
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167
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168 break;
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169
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170 /* anything we don't recognize as a statement token breaks out */
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171 default:
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172 return;
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173 }
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174 if (state -> lexer_token != token_eol)
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175 lwb_error("Expecting end of line; got %s\n", lexer_return_token(state));
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176 lexer(state);
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177 }
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178 }
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179
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181 /* issub means RETURNS is not allowed; !issub means RETURNS is required */
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
182
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
183 static void parse_subfunc(cstate *state, int issub)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
184 {
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
185 int pt, rt;
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
186 char *subname, *pn;
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
187 int vis = 0;
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
188 symtab_entry_t *se;
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
189 int paramsize = 0;
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
190
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
191 state -> local_syms = symtab_init();
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
192 state -> framesize = 0;
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
193
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
194 lexer(state);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
195 if (state -> lexer_token != token_identifier)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
196 {
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
197 lwb_error("Invalid sub name '%s'", state -> lexer_token_string);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
198 }
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
199
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
200 subname = lw_strdup(state -> lexer_token_string);
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
201
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
202 lexer(state);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
203 if (state -> lexer_token == token_kw_public || state -> lexer_token == token_kw_private)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
204 {
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
205 if (state -> lexer_token == token_kw_public)
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
206 vis = 1;
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
207 lexer(state);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
208 }
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
209
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
210 /* ignore the "PARAMS" keyword if present */
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
211 if (state -> lexer_token == token_kw_params)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
212 lexer(state);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
213
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
214 if (state -> lexer_token == token_eol || state -> lexer_token == token_kw_returns)
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
215 goto noparms;
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
216
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
217 paramagain:
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
218 if (state -> lexer_token != token_identifier)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
219 {
31
574931d87abd Created a function to prettyprint the current lexer token
lost@l-w.ca
parents: 30
diff changeset
220 lwb_error("Parameter name expected, got %s\n", lexer_return_token(state));
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
221 }
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
222 pn = lw_strdup(state -> lexer_token_string);
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
223 lexer(state);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
224
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
225 if (state -> lexer_token != token_kw_as)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
226 lwb_error("Expecting AS\n");
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
227 lexer(state);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
228
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
229 pt = parse_type(state);
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
230
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
231 se = symtab_find(state -> local_syms, pn);
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
232 if (se)
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
233 {
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
234 lwb_error("Duplicate parameter name %s\n", pn);
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
235 }
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
236 symtab_register(state -> local_syms, pn, paramsize, symtype_param, NULL);
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
237 paramsize += sizeof_type(pt);
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
238 lw_free(pn);
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
239
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
240 if (state -> lexer_token == token_char && state -> lexer_token_string[0] == ',')
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
241 {
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
242 lexer(state);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
243 goto paramagain;
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
244 }
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
245
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
246 noparms:
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
247 rt = -1;
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
248 if (!issub)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
249 {
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
250 if (state -> lexer_token != token_kw_returns)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
251 {
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
252 lwb_error("FUNCTION must have RETURNS\n");
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
253 }
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
254 lexer(state);
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
255 /* if (state -> lexer_token == token_identifier)
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
256 {
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
257 printf("Return value named: %s\n", state -> lexer_token_string);
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
258
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
259 lexer(state);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
260 if (state -> lexer_token != token_kw_as)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
261 lwb_error("Execting AS after RETURNS");
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
262 lexer(state);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
263 }
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
264 */
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
265 rt = parse_type(state);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
266 }
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
267 else
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
268 {
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
269 if (state -> lexer_token == token_kw_returns)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
270 {
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
271 lwb_error("SUB cannot specify RETURNS\n");
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
272 }
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
273 }
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
274
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
275
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
276 if (state -> lexer_token != token_eol)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
277 {
31
574931d87abd Created a function to prettyprint the current lexer token
lost@l-w.ca
parents: 30
diff changeset
278 lwb_error("EOL expected; found %s\n", lexer_return_token(state));
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
279 }
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
280
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
281
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
282 se = symtab_find(state -> global_syms, subname);
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
283 if (se)
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
284 {
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
285 lwb_error("Multiply defined symbol %s\n", subname);
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
286 }
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
287
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
288 symtab_register(state -> global_syms, subname, -1, issub ? symtype_sub : symtype_func, NULL);
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
289
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
290 state -> currentsub = subname;
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
291 state -> returntype = rt;
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
292 /* consume EOL */
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
293 lexer(state);
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
294
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
295 /* variable declarations */
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
296 parse_decls(state);
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
297
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
298 /* output function/sub prolog */
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
299 emit_prolog(state, vis);
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
300
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
301 /* parse statement block */
34
bfea77812e64 Start of assignment code
Lost Wizard (lost@starbug3)
parents: 33
diff changeset
302 parse_statements(state);
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
303
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
304 if (issub)
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
305 {
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
306 if (state -> lexer_token != token_kw_endsub)
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
307 {
31
574931d87abd Created a function to prettyprint the current lexer token
lost@l-w.ca
parents: 30
diff changeset
308 lwb_error("Expecting ENDSUB, got %s\n", lexer_return_token(state));
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
309 }
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
310 }
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
311 else
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
312 {
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
313 if (state -> lexer_token != token_kw_endfunction)
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
314 {
31
574931d87abd Created a function to prettyprint the current lexer token
lost@l-w.ca
parents: 30
diff changeset
315 lwb_error("Expecting ENDFUNCTION, got %s\n", lexer_return_token(state));
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
316 }
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
317 }
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
318 /* output function/sub epilog */
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
319 emit_epilog(state);
26
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
320
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
321 lw_free(state -> currentsub);
26aa76da75ad Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents: 25
diff changeset
322 state -> currentsub = NULL;
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
323 symtab_destroy(state -> local_syms);
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
324 state -> local_syms = NULL;
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
325 }
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
326
30
bcd532a90e53 Renamed "compiler" to "parser" for more consistent terminology
lost@l-w.ca
parents: 27
diff changeset
327 void parser(cstate *state)
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
328 {
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
329 state -> lexer_curchar = -1;
32
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
330 state -> global_syms = symtab_init();
49d608aecc4d Framework for handling local stack frame and/or variables
lost@l-w.ca
parents: 31
diff changeset
331
25
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
332 /* now look for a global declaration */
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
333 for (;;)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
334 {
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
335 state -> parser_state = parser_state_global;
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
336 lexer(state);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
337 switch (state -> lexer_token)
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
338 {
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
339 case token_kw_function:
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
340 printf("Function\n");
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
341 parse_subfunc(state, 0);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
342 break;
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
343
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
344 case token_kw_sub:
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
345 printf("Sub\n");
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
346 parse_subfunc(state, 1);
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
347 break;
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
348
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
349 /* blank lines are allowed */
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
350 case token_eol:
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
351 continue;
87590f43e76d Started lwbasic parser; checkpoint
lost@l-w.ca
parents:
diff changeset
352
87590f43e76d Started lwbasic parser; checkpoint
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parents:
diff changeset
353 /* EOF is allowed - end of parsing */
87590f43e76d Started lwbasic parser; checkpoint
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parents:
diff changeset
354 case token_eof:
87590f43e76d Started lwbasic parser; checkpoint
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parents:
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355 return;
87590f43e76d Started lwbasic parser; checkpoint
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parents:
diff changeset
356
87590f43e76d Started lwbasic parser; checkpoint
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parents:
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357 default:
31
574931d87abd Created a function to prettyprint the current lexer token
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parents: 30
diff changeset
358 lwb_error("Invalid token '%s' in global state\n", lexer_return_token(state));
25
87590f43e76d Started lwbasic parser; checkpoint
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parents:
diff changeset
359 }
87590f43e76d Started lwbasic parser; checkpoint
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parents:
diff changeset
360 }
87590f43e76d Started lwbasic parser; checkpoint
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parents:
diff changeset
361 }
36
5325b640424d First pass expression parsing
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diff changeset
362
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diff changeset
363 static void parse_expr(cstate *state, int prec)
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diff changeset
364 {
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diff changeset
365 static const struct operinfo {
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366 int opernum;
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diff changeset
367 int operprec;
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diff changeset
368 } operators[] =
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369 {
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370 { token_op_plus, 100 },
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diff changeset
371 { token_op_minus, 100 },
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diff changeset
372 { token_op_times, 150 },
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diff changeset
373 { token_op_divide, 150 },
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diff changeset
374 { token_op_modulus, 150 },
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diff changeset
375 { token_op_and, 25 },
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diff changeset
376 { token_op_or, 20 },
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diff changeset
377 { token_op_xor, 20 },
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diff changeset
378 { token_op_band, 50 },
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diff changeset
379 { token_op_bor, 45 },
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diff changeset
380 { token_op_bxor, 45 },
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diff changeset
381 { -1, -1 }
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diff changeset
382 };
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diff changeset
383 int opern;
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diff changeset
384
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diff changeset
385 parse_term(state);
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diff changeset
386
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diff changeset
387 eval_next:
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diff changeset
388 for (opern = 0; operators[opern].opernum != -1; opern++)
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diff changeset
389 {
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diff changeset
390 if (operators[opern].opernum == state -> lexer_token)
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diff changeset
391 break;
5325b640424d First pass expression parsing
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diff changeset
392 }
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diff changeset
393 if (operators[opern].opernum == -1)
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diff changeset
394 return;
5325b640424d First pass expression parsing
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parents: 35
diff changeset
395
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diff changeset
396 if (operators[opern].operprec <= prec)
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diff changeset
397 return;
5325b640424d First pass expression parsing
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parents: 35
diff changeset
398
5325b640424d First pass expression parsing
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diff changeset
399 lexer(state);
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parents: 35
diff changeset
400
5325b640424d First pass expression parsing
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diff changeset
401 parse_expr(state, operators[opern].operprec);
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parents: 35
diff changeset
402
5325b640424d First pass expression parsing
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diff changeset
403 /* push operator */
5325b640424d First pass expression parsing
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parents: 35
diff changeset
404
5325b640424d First pass expression parsing
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parents: 35
diff changeset
405 goto eval_next;
5325b640424d First pass expression parsing
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parents: 35
diff changeset
406 }
5325b640424d First pass expression parsing
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parents: 35
diff changeset
407
5325b640424d First pass expression parsing
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diff changeset
408 static void parse_term(cstate *state)
5325b640424d First pass expression parsing
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diff changeset
409 {
5325b640424d First pass expression parsing
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diff changeset
410 eval_next:
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diff changeset
411 /* parens */
5325b640424d First pass expression parsing
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parents: 35
diff changeset
412 if (state -> lexer_token == token_op_oparen)
5325b640424d First pass expression parsing
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parents: 35
diff changeset
413 {
5325b640424d First pass expression parsing
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parents: 35
diff changeset
414 lexer(state);
5325b640424d First pass expression parsing
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parents: 35
diff changeset
415 parse_expr(state, 0);
5325b640424d First pass expression parsing
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parents: 35
diff changeset
416 expect(state, token_op_cparen);
5325b640424d First pass expression parsing
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parents: 35
diff changeset
417 return;
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
418 }
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
419
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
420 /* unary plus; ignore it */
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
421 if (state -> lexer_token == token_op_plus)
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
422 {
5325b640424d First pass expression parsing
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parents: 35
diff changeset
423 lexer(state);
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
424 goto eval_next;
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
425 }
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
426
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
427 /* unary minus, precision 200 */
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
428 if (state -> lexer_token == token_op_minus)
5325b640424d First pass expression parsing
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parents: 35
diff changeset
429 {
5325b640424d First pass expression parsing
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parents: 35
diff changeset
430 lexer(state);
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
431 parse_expr(state, 200);
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
432
5325b640424d First pass expression parsing
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parents: 35
diff changeset
433 /* push unary negation */
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
434 }
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
435
5325b640424d First pass expression parsing
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parents: 35
diff changeset
436 /* BNOT, NOT */
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
437 if (state -> lexer_token == token_op_not || state -> lexer_token == token_op_bnot)
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
438 {
5325b640424d First pass expression parsing
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parents: 35
diff changeset
439 lexer(state);
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
440 parse_expr(state, 200);
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
441
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
442 /* push unary operator */
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
443 }
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
444
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
445 /* integer */
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
446 if (state -> lexer_token == token_int)
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
447 {
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
448 }
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
449
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
450 /* unsigned integer */
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
451 if (state -> lexer_token == token_uint)
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
452 {
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
453 }
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
454
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
455 /* variable or function call */
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
456 if (state -> lexer_token == token_identifier)
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
457 {
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
458 lexer(state);
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
459 if (state -> lexer_token == token_op_oparen)
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
460 {
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
461 /* function call */
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
462 return;
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
463 }
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
464 /* variable */
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
465 return;
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
466 }
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
467
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
468 lwb_error("Invalid input in expression; got %s\n", lexer_return_token(state));
5325b640424d First pass expression parsing
Lost Wizard (lost@starbug3)
parents: 35
diff changeset
469 }