67 lines
1.4 KiB
Plaintext
67 lines
1.4 KiB
Plaintext
%{
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#include "parser.h"
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int stack[100]; // Max indentation depth
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int sp = -1;
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int peek();
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void push(int a);
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void pop();
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#define YY_USER_INIT push(0); BEGIN(freshline);
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%}
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%option noyywrap
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%x freshline
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digit [0-9]
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letter [A-Za-z]
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%%
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<freshline>""/[^\t ] {
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if (peek() == 0) {
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BEGIN(0);
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} else {
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pop(); yyless(0); return DEDENT;
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}
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}
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<freshline>[ \t]+ {
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if (peek() == yyleng) {
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BEGIN(0); // Same indentation, continue
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} else if (peek() > yyleng) {
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pop(); yyless(0); return DEDENT;
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// Same rule again until the stack is even
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} else {
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push(yyleng); BEGIN(0); return INDENT;
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}
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}
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#[^\n]* // Eat comments
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\"[^"]*\" yylval.sym = yytext; return STRING;
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if return IF;
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else return ELSE;
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elif return ELIF;
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{digit}+|{digit}*\.{digit}+ yylval.num = atof(yytext); return NUM;
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{letter}({letter}|{digit}|[?-])* yylval.sym = yytext; return ID;
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"<-" return GETS;
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"->" return MAPS;
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[(){}.,*/+-] return yytext[0];
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[\t ] // Eat whitespace not first on a line
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"/"\n // Eat newlines ending in /
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[\n;] BEGIN(freshline); return STOP;
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. fprintf(stderr, "Scanning error!\nOffender: %s\n", yytext); exit(1);
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%%
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int peek() {
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printf("Peek @ %d\n", stack[sp]);
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return stack[sp];
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}
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void push(int a) {
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printf("Push @ %d\n", a);
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sp++;
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stack[sp] = a;
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}
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void pop() {
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printf("Pop! Sp @ %d\n", sp);
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sp--;
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}
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