Practica 3 Diego Anaya A01663765

labs/03/lab03.l

@@ -0,0 +1,20 @@
+%{
+#include "y.tab.h"
+%}
+
+%%
+
+"a"|"the"                { return ARTICLE; }
+"boy"|"girl"|"flower"    { return NOUN; }
+"touches"|"likes"|"sees" { return VERB; }
+"with"                   { return PREPOSITION; }
+[\t]+                    ; /* ignore whitespace */
+\n                       { return EOL; }
+.                        ; /* ignore other characters */
+
+%%
+
+int yywrap(void) {
+    return 1;
+}
+

labs/03/lab03.y

@@ -0,0 +1,64 @@
+%{
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+int yylex();
+void yyerror(const char *s);
+extern FILE *yyin;
+%}
+
+%token ARTICLE NOUN VERB PREPOSITION EOL
+
+%%
+
+sentences
+    : /* empty */
+    | sentences sentence EOL { printf("PASS\n"); }
+    | sentences error EOL    { printf("FAIL\n"); yyerrok; yyclearin; }
+    ;
+
+sentence
+    : noun_phrase verb_phrase
+    ;
+
+noun_phrase
+    : ARTICLE NOUN
+    | ARTICLE NOUN prep_phrase
+    ;
+
+verb_phrase
+    : VERB
+    | VERB noun_phrase
+    | VERB prep_phrase
+    ;
+
+prep_phrase
+    : PREPOSITION noun_phrase
+    ;
+
+%%
+
+int main(int argc, char **argv) {
+    if (argc != 2) {
+        fprintf(stderr, "Usage: %s filename\n", argv[0]);
+        exit(1);
+    }
+
+    yyin = fopen(argv[1], "r");
+    if (!yyin) {
+        perror(argv[1]);
+        exit(1);
+    }
+
+    do {
+        yyparse();
+    } while (!feof(yyin));
+
+    fclose(yyin);
+    return 0;
+}
+
+void yyerror(const char *s) {
+    fprintf(stderr, "Error: %s\n", s);
+}
+