Mercurial > hg > index.cgi
annotate lwbasic/attic/parser.c @ 207:07e1fac76321
Added pragma to allow non case sensitive symbols
Added "nosymbolcase" and "symbolnocase" pragmas to cause symbols defined
while the pragma is in effect to be treated as case insensitive. Also
documented the new pragma.
| author | William Astle <lost@l-w.ca> |
|---|---|
| date | Sat, 09 Jun 2012 15:47:22 -0600 |
| parents | cca933d32298 |
| children |
| 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 | |
|
26
26aa76da75ad
Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents:
25
diff
changeset
|
28 #include <lw_alloc.h> |
|
26aa76da75ad
Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents:
25
diff
changeset
|
29 #include <lw_string.h> |
|
26aa76da75ad
Additional parsing in function/sub; emission of prolog/epilog code
lost@l-w.ca
parents:
25
diff
changeset
|
30 |
| 25 | 31 #include "lwbasic.h" |
|
32
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
32 #include "symtab.h" |
|
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
33 |
| 34 | 34 static void expect(cstate *state, int tt) |
| 35 { | |
| 36 if (state -> lexer_token != tt) | |
| 37 lwb_error("Expecting %s, got %s\n", lexer_token_name(tt), lexer_return_token(state)); | |
| 38 lexer(state); | |
| 39 } | |
| 40 | |
|
32
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
41 |
|
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
42 /* size of a type */ |
|
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
43 static int sizeof_type(int type) |
|
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
44 { |
|
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
45 /* everything is an "int" right now; 2 bytes */ |
|
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
46 return 2; |
|
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
47 } |
| 25 | 48 |
| 49 /* parse a type; the next token will be acquired as a result */ | |
| 50 /* the token advancement is to provide consistency */ | |
| 51 static int parse_type(cstate *state) | |
| 52 { | |
| 53 int pt = -1; | |
| 54 | |
| 55 switch (state -> lexer_token) | |
| 56 { | |
| 57 case token_kw_integer: | |
| 58 pt = 1; | |
| 59 break; | |
| 60 | |
| 61 default: | |
| 62 lwb_error("Invalid type specification"); | |
| 63 } | |
| 64 lexer(state); | |
| 65 /* look for "unsigned" modifier for integer types */ | |
| 66 return pt; | |
| 67 } | |
| 68 | |
| 36 | 69 static void parse_expr(cstate *state, int prec); |
| 70 static void parse_term(cstate *state); | |
| 35 | 71 static int parse_expression(cstate *state) |
| 72 { | |
| 73 state -> expression = 1; | |
| 74 | |
| 36 | 75 parse_expr(state, 0); |
| 76 | |
| 35 | 77 state -> expression = 0; |
| 78 return 1; | |
| 79 } | |
| 80 | |
|
32
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
81 static void parse_decls(cstate *state) |
|
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
82 { |
|
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
83 /* declarations */ |
| 33 | 84 /* the first thing that doesn't look like a declaration is assumed */ |
| 85 /* to be a statement and will trigger a bailout */ | |
| 86 int vt; | |
| 87 char *vn; | |
| 88 symtab_entry_t *se; | |
| 89 | |
| 90 for (;;) | |
|
32
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
91 { |
| 33 | 92 switch (state -> lexer_token) |
| 93 { | |
| 94 /* DIM keyword */ | |
| 95 case token_kw_dim: | |
| 96 lexer(state); | |
| 97 if (state -> lexer_token != token_identifier) | |
| 98 { | |
| 99 lwb_error("Expecting identifier, got %s\n", lexer_return_token(state)); | |
| 100 } | |
| 101 vn = lw_strdup(state -> lexer_token_string); | |
| 102 lexer(state); | |
| 103 if (state -> lexer_token != token_kw_as) | |
| 104 { | |
| 105 lwb_error("Expecting AS, got %s\n", lexer_return_token(state)); | |
| 106 } | |
| 107 lexer(state); | |
| 108 vt = parse_type(state); | |
| 109 | |
| 110 se = symtab_find(state -> local_syms, vn); | |
| 111 if (se) | |
| 112 { | |
| 113 lwb_error("Multiply defined local variable %s", vn); | |
| 114 } | |
| 115 state -> framesize += sizeof_type(vt); | |
| 116 symtab_register(state -> local_syms, vn, -(state -> framesize), symtype_var, NULL); | |
| 117 | |
| 118 lw_free(vn); | |
| 119 break; | |
| 34 | 120 |
| 121 /* blank lines allowed */ | |
| 122 case token_eol: | |
| 123 break; | |
| 124 | |
| 33 | 125 default: |
| 126 return; | |
| 127 } | |
| 128 if (state -> lexer_token != token_eol) | |
| 34 | 129 lwb_error("Expecting end of line; got %s\n", lexer_return_token(state)); |
| 130 lexer(state); | |
| 131 } | |
| 132 } | |
| 133 | |
| 134 static void parse_statements(cstate *state) | |
| 135 { | |
| 136 symtab_entry_t *se; | |
| 35 | 137 int et; |
| 34 | 138 |
| 139 for (;;) | |
| 140 { | |
| 141 switch (state -> lexer_token) | |
| 142 { | |
| 143 /* blank lines allowed */ | |
| 144 case token_eol: | |
| 145 break; | |
| 146 | |
| 147 /* variable assignment */ | |
| 148 case token_identifier: | |
| 149 se = symtab_find(state -> local_syms, state -> lexer_token_string); | |
| 150 if (!se) | |
| 151 { | |
| 152 se = symtab_find(state -> global_syms, state -> lexer_token_string); | |
| 153 } | |
| 154 if (!se) | |
| 155 lwb_error("Unknown variable %s\n", state -> lexer_token_string); | |
| 156 lexer(state); | |
| 35 | 157 /* ensure the first token of the expression will be parsed correctly */ |
| 158 state -> expression = 1; | |
| 34 | 159 expect(state, token_op_assignment); |
| 160 | |
| 161 /* parse the expression */ | |
| 35 | 162 et = parse_expression(state); |
| 163 | |
| 164 /* check type compatibility */ | |
| 34 | 165 |
| 166 /* actually do the assignment */ | |
| 167 | |
| 168 break; | |
| 169 | |
| 170 /* anything we don't recognize as a statement token breaks out */ | |
| 171 default: | |
| 172 return; | |
| 173 } | |
| 174 if (state -> lexer_token != token_eol) | |
| 175 lwb_error("Expecting end of line; got %s\n", lexer_return_token(state)); | |
| 33 | 176 lexer(state); |
|
32
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
177 } |
|
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
178 } |
|
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
179 |
| 25 | 180 |
| 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 | 183 static void parse_subfunc(cstate *state, int issub) |
| 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 | 194 lexer(state); |
| 195 if (state -> lexer_token != token_identifier) | |
| 196 { | |
| 197 lwb_error("Invalid sub name '%s'", state -> lexer_token_string); | |
| 198 } | |
| 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 | 201 |
| 202 lexer(state); | |
| 203 if (state -> lexer_token == token_kw_public || state -> lexer_token == token_kw_private) | |
| 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 | 207 lexer(state); |
| 208 } | |
| 209 | |
| 210 /* ignore the "PARAMS" keyword if present */ | |
| 211 if (state -> lexer_token == token_kw_params) | |
| 212 lexer(state); | |
| 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 | 215 goto noparms; |
| 216 | |
| 217 paramagain: | |
| 218 if (state -> lexer_token != token_identifier) | |
| 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 | 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 | 223 lexer(state); |
| 224 | |
| 225 if (state -> lexer_token != token_kw_as) | |
| 226 lwb_error("Expecting AS\n"); | |
| 227 lexer(state); | |
| 228 | |
| 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 | 239 |
| 240 if (state -> lexer_token == token_char && state -> lexer_token_string[0] == ',') | |
| 241 { | |
| 242 lexer(state); | |
| 243 goto paramagain; | |
| 244 } | |
| 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 | 248 if (!issub) |
| 249 { | |
| 250 if (state -> lexer_token != token_kw_returns) | |
| 251 { | |
| 252 lwb_error("FUNCTION must have RETURNS\n"); | |
| 253 } | |
| 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 | 256 { |
| 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 | 259 lexer(state); |
| 260 if (state -> lexer_token != token_kw_as) | |
| 261 lwb_error("Execting AS after RETURNS"); | |
| 262 lexer(state); | |
| 263 } | |
|
32
49d608aecc4d
Framework for handling local stack frame and/or variables
lost@l-w.ca
parents:
31
diff
changeset
|
264 */ |
| 25 | 265 rt = parse_type(state); |
| 266 } | |
| 267 else | |
| 268 { | |
| 269 if (state -> lexer_token == token_kw_returns) | |
| 270 { | |
| 271 lwb_error("SUB cannot specify RETURNS\n"); | |
| 272 } | |
| 273 } | |
| 274 | |
| 275 | |
| 276 if (state -> lexer_token != token_eol) | |
| 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 | 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 | 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 | 325 } |
| 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 | 328 { |
| 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 | 332 /* now look for a global declaration */ |
| 333 for (;;) | |
| 334 { | |
| 335 state -> parser_state = parser_state_global; | |
| 336 lexer(state); | |
| 337 switch (state -> lexer_token) | |
| 338 { | |
| 339 case token_kw_function: | |
| 340 printf("Function\n"); | |
| 341 parse_subfunc(state, 0); | |
| 342 break; | |
| 343 | |
| 344 case token_kw_sub: | |
| 345 printf("Sub\n"); | |
| 346 parse_subfunc(state, 1); | |
| 347 break; | |
| 348 | |
| 349 /* blank lines are allowed */ | |
| 350 case token_eol: | |
| 351 continue; | |
| 352 | |
| 353 /* EOF is allowed - end of parsing */ | |
| 354 case token_eof: | |
| 355 return; | |
| 356 | |
| 357 default: | |
|
31
574931d87abd
Created a function to prettyprint the current lexer token
lost@l-w.ca
parents:
30
diff
changeset
|
358 lwb_error("Invalid token '%s' in global state\n", lexer_return_token(state)); |
| 25 | 359 } |
| 360 } | |
| 361 } | |
| 36 | 362 |
| 363 static void parse_expr(cstate *state, int prec) | |
| 364 { | |
| 365 static const struct operinfo { | |
| 366 int opernum; | |
| 367 int operprec; | |
| 368 } operators[] = | |
| 369 { | |
| 370 { token_op_plus, 100 }, | |
| 371 { token_op_minus, 100 }, | |
| 372 { token_op_times, 150 }, | |
| 373 { token_op_divide, 150 }, | |
| 374 { token_op_modulus, 150 }, | |
| 375 { token_op_and, 25 }, | |
| 376 { token_op_or, 20 }, | |
| 377 { token_op_xor, 20 }, | |
| 378 { token_op_band, 50 }, | |
| 379 { token_op_bor, 45 }, | |
| 380 { token_op_bxor, 45 }, | |
| 381 { -1, -1 } | |
| 382 }; | |
| 383 int opern; | |
| 384 | |
| 385 parse_term(state); | |
| 386 | |
| 387 eval_next: | |
| 388 for (opern = 0; operators[opern].opernum != -1; opern++) | |
| 389 { | |
| 390 if (operators[opern].opernum == state -> lexer_token) | |
| 391 break; | |
| 392 } | |
| 393 if (operators[opern].opernum == -1) | |
| 394 return; | |
| 395 | |
| 396 if (operators[opern].operprec <= prec) | |
| 397 return; | |
| 398 | |
| 399 lexer(state); | |
| 400 | |
| 401 parse_expr(state, operators[opern].operprec); | |
| 402 | |
| 403 /* push operator */ | |
| 404 | |
| 405 goto eval_next; | |
| 406 } | |
| 407 | |
| 408 static void parse_term(cstate *state) | |
| 409 { | |
| 410 eval_next: | |
| 411 /* parens */ | |
| 412 if (state -> lexer_token == token_op_oparen) | |
| 413 { | |
| 414 lexer(state); | |
| 415 parse_expr(state, 0); | |
| 416 expect(state, token_op_cparen); | |
| 417 return; | |
| 418 } | |
| 419 | |
| 420 /* unary plus; ignore it */ | |
| 421 if (state -> lexer_token == token_op_plus) | |
| 422 { | |
| 423 lexer(state); | |
| 424 goto eval_next; | |
| 425 } | |
| 426 | |
| 427 /* unary minus, precision 200 */ | |
| 428 if (state -> lexer_token == token_op_minus) | |
| 429 { | |
| 430 lexer(state); | |
| 431 parse_expr(state, 200); | |
| 432 | |
| 433 /* push unary negation */ | |
| 434 } | |
| 435 | |
| 436 /* BNOT, NOT */ | |
| 437 if (state -> lexer_token == token_op_not || state -> lexer_token == token_op_bnot) | |
| 438 { | |
| 439 lexer(state); | |
| 440 parse_expr(state, 200); | |
| 441 | |
| 442 /* push unary operator */ | |
| 443 } | |
| 444 | |
| 445 /* integer */ | |
| 446 if (state -> lexer_token == token_int) | |
| 447 { | |
| 448 } | |
| 449 | |
| 450 /* unsigned integer */ | |
| 451 if (state -> lexer_token == token_uint) | |
| 452 { | |
| 453 } | |
| 454 | |
| 455 /* variable or function call */ | |
| 456 if (state -> lexer_token == token_identifier) | |
| 457 { | |
| 458 lexer(state); | |
| 459 if (state -> lexer_token == token_op_oparen) | |
| 460 { | |
| 461 /* function call */ | |
| 462 return; | |
| 463 } | |
| 464 /* variable */ | |
| 465 return; | |
| 466 } | |
| 467 | |
| 468 lwb_error("Invalid input in expression; got %s\n", lexer_return_token(state)); | |
| 469 } |