224 lines
6.5 KiB
C
224 lines
6.5 KiB
C
/** @license 2022 Neil Edelman, distributed under the terms of the
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[MIT License](https://opensource.org/licenses/MIT).
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Lexer for journal entries.
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@std C89/90 */
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#include "../src/lex.h"
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#include <stdlib.h>
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#include <stdio.h>
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#include <assert.h>
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#include <limits.h>
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#include <errno.h>
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/*!re2c
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re2c:yyfill:enable = 0;
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re2c:define:YYCTYPE = char;
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*/
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int lex_looks_like_year(const char *const a, int *const year) {
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const char *YYCURSOR = a, *YYMARKER = a, *s0;
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/*!stags:re2c format = 'const char *@@;\n'; */
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(void)yyt2, (void)yyt3;
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assert(a && year);
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/*!re2c
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@s0 ("-"? [1-9][0-9]* | "0") "\x00" {
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int sign = 1, mag;
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if(*s0 == '-') { sign = -1; s0++; }
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for(mag = 0; *s0 != '\0'; s0++) {
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int d = *s0 - '0';
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if((INT_MAX - d) / 10 < mag) return 0;
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mag = mag * 10 + d;
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}
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*year = sign * mag;
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return 1;
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}
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* { return 0; }
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*/
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}
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int lex_looks_like_month(const char *const a) {
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const char *YYCURSOR = a, *YYMARKER = a, *s0;
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/*!stags:re2c format = 'const char *@@;\n'; */
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(void)yyt1, (void)yyt2, (void)yyt3;
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assert(a);
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/*!re2c
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@s0 [0-1][0-9] "\x00" {
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int val = 10 * (s0[0] - '0') + (s0[1] - '0');
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return val < 1 || val > 12 ? 0 : val;
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}
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* { return 0; }
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*/
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}
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int lex_looks_like_day(const char *const a) {
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const char *YYCURSOR = a, *YYMARKER = a, *s0;
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/*!stags:re2c format = 'const char *@@;\n'; */
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(void)yyt1, (void)yyt2, (void)yyt3;
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assert(a);
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/*!re2c
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@s0 [0-3][0-9] ".txt\x00" {
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int val = 10 * (s0[0] - '0') + (s0[1] - '0');
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return val < 1 || val > 31 ? 0 : val;
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}
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* { return 0; }
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*/
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}
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/* This defines `enum condition`. */
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/*!types:re2c*/
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/* "[edict: expect; there; to; be; args]", in this case, expect would be a
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stack of `size = 5` `EXPECT_KEYWORD`. This mirrors arguments in `LEX_SYMBOL`
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and should also be an `edict_*` in <fn:lex_next> and <fn:expect_pop>. */
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#define EXPECT_HEAD X(keyword, KEYWORD) X(date, DATE)
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#define EXPECT_CONS Y(freeform, FREEFORM)
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#define EXPECT EXPECT_HEAD EXPECT_CONS
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/** scanner reads a file and extracts semantic information. Valid to access
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only while underlying pointers do not change. */
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static struct scan {
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/* `re2c` variables; these point directly into `buffer`. */
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const char *marker, *ctx_marker, *from, *cursor;
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/* Weird `c2re` stuff: these fields have to come after when >5? */
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const char *label, *buffer;
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enum condition condition;
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size_t line;
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int is_ws_expected, is_source;
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#define X(n, N) EXPECT_ ## N,
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#define Y(n, N) EXPECT_ ## N
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struct { unsigned size; enum { EXPECT } expect[16]; } edict;
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#undef X
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#undef Y
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} scan; /* Not suited for concurrency. Simple. */
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/** Resets the buffer to some `buffer`. */
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void lex_reset(const char *const buffer) {
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scan.marker = scan.ctx_marker = scan.from = scan.cursor = scan.label
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= scan.buffer = buffer;
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scan.condition = yycline;
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scan.line = 1;
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}
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/** I don't think `re2c` supports branching on variable conditions.
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It does now? */
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static void expect_pop(void) {
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if(!scan.edict.size) { scan.condition = yycedict_end; return; }
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switch(scan.edict.expect[--scan.edict.size]) {
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#define X(n, N) case EXPECT_ ## N : scan.condition = yycedict_ ## n; break;
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#define Y(n, N) case EXPECT_ ## N : scan.condition = yycedict_ ## n; break;
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EXPECT
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#undef X
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#undef Y
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}
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}
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int lex_next(struct lex *const x) {
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/*!re2c
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re2c:flags:tags = 1;
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re2c:define:YYCURSOR = scan.cursor;
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re2c:define:YYMARKER = scan.marker;
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re2c:define:YYCTXMARKER = scan.ctx_marker;
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re2c:define:YYCONDTYPE = 'condition';
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re2c:define:YYGETCONDITION = 'scan.condition';
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re2c:define:YYGETCONDITION:naked = 1;
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re2c:define:YYSETCONDITION = 'scan.condition = @@;';
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re2c:define:YYSETCONDITION:naked = 1;
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*/
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const char *s0, *s1;
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/*!stags:re2c format = 'const char *@@;\n'; */
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assert(x);
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if(!scan.buffer) return 0;
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x->s0 = x->s1 = 0;
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scan:
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/*!re2c
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sentinel = "\x00";
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illegal = [\x01-\x08\x0a-\x1f\x7f]; // unix-style control characters
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newline = "\n";
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ws = [ \t];
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glyph = [^\x00-\x1f \x7f];
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<*> illegal { return x->symbol = ILLEGAL, 0; }
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<line> sentinel { return x->symbol = END, 0; }
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<text, text, image, edict, edict_keyword, edict_date, edict_freeform, edict_end>
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sentinel { return x->symbol = ILLEGAL, 0; }
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<line> newline { x->line = ++scan.line; return x->symbol = PARAGRAPH, 1; }
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<line> "![" :=> image
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<line> "[" :=> edict
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<line> "" / glyph :=> text
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<line> * { return x->symbol = SYNTAX, 1; }
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<text> newline => line { x->line = ++scan.line; goto scan; }
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<text> ws+ { goto scan; }
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<text> @s0 glyph+ @s1 { x->s0 = s0, x->s1 = s1;
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return x->symbol = TEXT, 1; }
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decimal = "-"? ([1-9][0-9]* | [0])? "." [0-9]+ | [1-9][0-9]* | [0];
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<image> ws* "osm" ws* "](geo:" @s0 decimal "," @s1 decimal ")" => text {
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x->symbol = MAP, x->s0 = s0, x->s1 = s1;
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printf("Got a map.\n");
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return 1;
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}
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<image> * { printf("image(broken)\n");return 0; }
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//
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natural = [1-9][0-9]*;
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id = [a-zA-Z_][a-zA-Z_\-0-9]{0,63};
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date = "-"? natural "-" [0-1][0-9] "-" [0-1][0-9];
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<edict> "source"
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{ if(scan.is_ws_expected || scan.edict.size)
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return x->symbol = SYNTAX, 0;
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scan.is_ws_expected = 1, scan.is_source = 1;
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scan.edict.size = 2;
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scan.edict.expect[1] = EXPECT_KEYWORD;
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scan.edict.expect[0] = EXPECT_FREEFORM;
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return x->symbol = SOURCE, 1; }
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<edict> "default"
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{ if(scan.is_ws_expected || !scan.is_source)
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return x->symbol = SYNTAX, 0;
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scan.is_ws_expected = 1, scan.is_source = 0;
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return x->symbol = DEFAULT, 1; }
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// score
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<edict> "significant"
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{ if(scan.is_ws_expected || scan.edict.size)
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return x->symbol = SYNTAX, 0;
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scan.is_ws_expected = 1;
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scan.edict.size = 2;
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scan.edict.expect[1] = EXPECT_FREEFORM;
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scan.edict.expect[0] = EXPECT_DATE;
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return x->symbol = SIGNIFICANT, 1; }
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<edict> @s0 natural @s1
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{ if(scan.is_ws_expected || scan.edict.size)
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return x->symbol = SYNTAX, 0;
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scan.is_ws_expected = 1;
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x->s0 = s0, x->s1 = s1;
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return x->symbol = SCORE, 1; }
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<edict> ws+ { scan.is_ws_expected = 0; goto scan; }
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<edict> ":"
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{ if(!scan.edict.size) return x->symbol = SYNTAX, 0;
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scan.is_ws_expected = 0, scan.is_source = 0;
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expect_pop(); goto scan; }
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<! edict_keyword, edict_date, edict_freeform> { expect_pop(); }
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<edict_keyword> ws* @s0 id @s1 ws* ";"? / "]"?
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{ x->s0 = s0, x->s1 = s1;
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return x->symbol = ARG_KEYWORD, 1; }
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<edict_date> ws* @s0 date @s1 ws* ";"? / "]"?
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{ x->s0 = s0, x->s1 = s1;
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return x->symbol = ARG_DATE, 1; }
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<edict_freeform> ws* @s0
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[^ \t\n\r\v\f;[\]\x00][^\t\n\r\v\f;[\]\x00]*[^ \t\n\r\v\f;[\]\x00]*
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@s1 ws* ";"? / "]"?
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{ x->s0 = s0, x->s1 = s1;
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return x->symbol = ARG_FREEFORM, 1; }
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<edict, edict_end> "]" => text
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{ if(scan.edict.size) return 0;
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goto scan; }
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<edict, edict_keyword, edict_date, edict_freeform, edict_end> *
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{ return x->symbol = SYNTAX, 0; }
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*/
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}
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