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annotate lwbasic/parser.c @ 30:bcd532a90e53
Renamed "compiler" to "parser" for more consistent terminology
| author | lost@l-w.ca |
|---|---|
| date | Thu, 03 Feb 2011 21:19:11 -0700 |
| parents | lwbasic/compiler.c@77626fc37af2 |
| children | 574931d87abd |
| rev | line source |
|---|---|
| 25 | 1 /* |
| 2 compiler.c | |
| 3 | |
| 4 Copyright © 2011 William Astle | |
| 5 | |
| 6 This file is part of LWTOOLS. | |
| 7 | |
| 8 LWTOOLS is free software: you can redistribute it and/or modify it under the | |
| 9 terms of the GNU General Public License as published by the Free Software | |
| 10 Foundation, either version 3 of the License, or (at your option) any later | |
| 11 version. | |
| 12 | |
| 13 This program is distributed in the hope that it will be useful, but WITHOUT | |
| 14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
| 16 more details. | |
| 17 | |
| 18 You should have received a copy of the GNU General Public License along with | |
| 19 this program. If not, see <http://www.gnu.org/licenses/>. | |
| 20 */ | |
| 21 | |
| 22 /* | |
| 23 This is the actual compiler bit; it drives the parser and code generation | |
| 24 */ | |
| 25 | |
| 26 #include <stdio.h> | |
| 27 | |
|
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28 #include <lw_alloc.h> |
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29 #include <lw_string.h> |
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30 |
| 25 | 31 #include "lwbasic.h" |
| 32 | |
| 33 /* parse a type; the next token will be acquired as a result */ | |
| 34 /* the token advancement is to provide consistency */ | |
| 35 static int parse_type(cstate *state) | |
| 36 { | |
| 37 int pt = -1; | |
| 38 | |
| 39 switch (state -> lexer_token) | |
| 40 { | |
| 41 case token_kw_integer: | |
| 42 pt = 1; | |
| 43 break; | |
| 44 | |
| 45 default: | |
| 46 lwb_error("Invalid type specification"); | |
| 47 } | |
| 48 lexer(state); | |
| 49 /* look for "unsigned" modifier for integer types */ | |
| 50 return pt; | |
| 51 } | |
| 52 | |
| 53 | |
| 54 /* issub means RETURNS is not allowed; !issub means RETURNS is required */ | |
| 55 static void parse_subfunc(cstate *state, int issub) | |
| 56 { | |
| 57 int pt; | |
|
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58 char *subname; |
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59 int vis = 0; |
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60 |
| 25 | 61 lexer(state); |
| 62 if (state -> lexer_token != token_identifier) | |
| 63 { | |
| 64 lwb_error("Invalid sub name '%s'", state -> lexer_token_string); | |
| 65 } | |
| 66 | |
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67 subname = lw_strdup(state -> lexer_token_string); |
| 25 | 68 |
| 69 lexer(state); | |
| 70 if (state -> lexer_token == token_kw_public || state -> lexer_token == token_kw_private) | |
| 71 { | |
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72 if (state -> lexer_token == token_kw_public) |
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73 vis = 1; |
| 25 | 74 lexer(state); |
| 75 } | |
| 76 | |
| 77 /* ignore the "PARAMS" keyword if present */ | |
| 78 if (state -> lexer_token == token_kw_params) | |
| 79 lexer(state); | |
| 80 | |
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81 if (state -> lexer_token == token_eol || state -> lexer_token == token_kw_returns) |
| 25 | 82 goto noparms; |
| 83 | |
| 84 paramagain: | |
| 85 if (state -> lexer_token != token_identifier) | |
| 86 { | |
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87 lwb_error("Parameter name expected, got %d, %s\n", state -> lexer_token, state -> lexer_token_string); |
| 25 | 88 } |
| 89 printf("Got <param> = %s\n", state -> lexer_token_string); | |
| 90 lexer(state); | |
| 91 | |
| 92 if (state -> lexer_token != token_kw_as) | |
| 93 lwb_error("Expecting AS\n"); | |
| 94 lexer(state); | |
| 95 | |
| 96 pt = parse_type(state); | |
| 97 printf("Got <type> = %d\n", pt); | |
| 98 | |
| 99 if (state -> lexer_token == token_char && state -> lexer_token_string[0] == ',') | |
| 100 { | |
| 101 lexer(state); | |
| 102 goto paramagain; | |
| 103 } | |
| 104 | |
| 105 noparms: | |
| 106 if (!issub) | |
| 107 { | |
| 108 int rt; | |
| 109 | |
| 110 if (state -> lexer_token != token_kw_returns) | |
| 111 { | |
| 112 lwb_error("FUNCTION must have RETURNS\n"); | |
| 113 } | |
| 114 lexer(state); | |
| 115 if (state -> lexer_token == token_identifier) | |
| 116 { | |
| 117 printf("Return value named: %s\n", state -> lexer_token_string); | |
| 118 lexer(state); | |
| 119 if (state -> lexer_token != token_kw_as) | |
| 120 lwb_error("Execting AS after RETURNS"); | |
| 121 lexer(state); | |
| 122 } | |
| 123 rt = parse_type(state); | |
| 124 printf("Return type: %d\n", rt); | |
| 125 } | |
| 126 else | |
| 127 { | |
| 128 if (state -> lexer_token == token_kw_returns) | |
| 129 { | |
| 130 lwb_error("SUB cannot specify RETURNS\n"); | |
| 131 } | |
| 132 } | |
| 133 | |
| 134 | |
| 135 if (state -> lexer_token != token_eol) | |
| 136 { | |
| 137 lwb_error("EOL expected; found %d, %s\n", state -> lexer_token, state -> lexer_token_string); | |
| 138 } | |
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139 |
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140 |
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141 printf("Sub/Func %s, vis %s\n", subname, vis ? "public" : "private"); |
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142 |
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143 state -> currentsub = subname; |
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144 |
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145 /* consume EOL */ |
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146 lexer(state); |
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147 |
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148 /* variable declarations */ |
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149 /* parse_decls(state); */ |
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150 |
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151 /* output function/sub prolog */ |
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152 emit_prolog(state, vis, 0); |
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153 |
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154 /* parse statement block */ |
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155 /* parse_statemetns(state); */ |
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156 |
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157 if (issub) |
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158 { |
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159 if (state -> lexer_token != token_kw_endsub) |
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160 { |
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161 lwb_error("Expecting ENDSUB, got %d (%s)\n", state -> lexer_token, state -> lexer_token_string); |
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162 } |
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163 } |
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164 else |
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165 { |
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166 if (state -> lexer_token != token_kw_endfunction) |
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167 { |
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168 lwb_error("Expecting ENDFUNCTION, got %d (%s)\n", state -> lexer_token, state -> lexer_token_string); |
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169 } |
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170 } |
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171 /* output function/sub epilog */ |
| 27 | 172 emit_epilog(state, 0); |
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173 |
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174 lw_free(state -> currentsub); |
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175 state -> currentsub = NULL; |
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176 |
| 25 | 177 } |
| 178 | |
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179 void parser(cstate *state) |
| 25 | 180 { |
| 181 state -> lexer_curchar = -1; | |
| 182 | |
| 183 /* now look for a global declaration */ | |
| 184 for (;;) | |
| 185 { | |
| 186 state -> parser_state = parser_state_global; | |
| 187 lexer(state); | |
| 188 switch (state -> lexer_token) | |
| 189 { | |
| 190 case token_kw_function: | |
| 191 printf("Function\n"); | |
| 192 parse_subfunc(state, 0); | |
| 193 break; | |
| 194 | |
| 195 case token_kw_sub: | |
| 196 printf("Sub\n"); | |
| 197 parse_subfunc(state, 1); | |
| 198 break; | |
| 199 | |
| 200 /* blank lines are allowed */ | |
| 201 case token_eol: | |
| 202 continue; | |
| 203 | |
| 204 /* EOF is allowed - end of parsing */ | |
| 205 case token_eof: | |
| 206 return; | |
| 207 | |
| 208 default: | |
| 209 lwb_error("Invalid token %d, %s in global state\n", state -> lexer_token, state -> lexer_token_string); | |
| 210 } | |
| 211 } | |
| 212 } |