| 1 | // re2c example
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| 2 | //
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| 3 | // Similar to https://re2c.org/manual/manual_c.html
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| 4 |
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| 5 | // Demos:
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| 6 | //
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| 7 | // - Unreachable code - add unreachable
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| 8 | // - Unhandled input - comment out * clause (more convincing in our huge lexer)
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| 9 |
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| 10 | #include <assert.h> // assert
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| 11 | #include <stdio.h> // printf
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| 12 |
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| 13 |
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| 14 | /*!re2c
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| 15 | re2c:yyfill:enable = 0;
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| 16 | re2c:define:YYCTYPE = char;
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| 17 |
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| 18 | // Define rule for C-style strings with backslash escapes.
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| 19 | //
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| 20 | // \x00 is for the sentinel. re2c warns you that the sentinel should not be
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| 21 | // matched in a pattern.
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| 22 |
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| 23 | favorite = ["] ( [^\x00"\\] | "\\" [^\x00] )* ["];
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| 24 |
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| 25 | unreachable = "\"\"";
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| 26 |
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| 27 | favorite2 = ["] ( [^\x00"\\] | "\\z" )* ["];
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| 28 | */
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| 29 |
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| 30 | bool MatchDoubleQuotedString(const char *s) {
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| 31 | const char *YYCURSOR = s;
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| 32 | const char *YYMARKER; // depending on pattern, generated code may use this
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| 33 |
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| 34 | /*!re2c
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| 35 | favorite { return true; }
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| 36 | * { return false; }
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| 37 | */
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| 38 |
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| 39 | assert(0);
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| 40 | }
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| 41 |
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| 42 | int main(int argc, char **argv) {
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| 43 | char *s = argv[1];
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| 44 | bool matched = MatchDoubleQuotedString(s);
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| 45 |
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| 46 | if (matched) {
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| 47 | printf("YES %s\n", s);
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| 48 | } else {
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| 49 | printf("NO %s\n", s);
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| 50 | }
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| 51 |
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| 52 | return 0;
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| 53 | }
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