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Diffstat (limited to 'examples/manual/front.y')
-rw-r--r-- | examples/manual/front.y | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/examples/manual/front.y b/examples/manual/front.y new file mode 100644 index 0000000..77b5ca1 --- /dev/null +++ b/examples/manual/front.y @@ -0,0 +1,118 @@ +/* C code supplied at the beginning of the file. */ + +%{ + +#include <stdio.h> +#include <string.h> + +extern int yylexlinenum; /* these are in YYlex */ +extern char *yytext; /* current token */ + + +%} + +/* Keywords and reserved words begin here. */ + +%union{ /* this is the data union */ + char name[128]; /* names */ +} + +/*-------------------- the reserved words -----------------------------*/ + +%token PERIOD +%token NEWLINE +%token POSITIONAL + +%token VERB +%token ADVERB + +%token PROPER_NOUN +%token NOUN + +%token DECLARATIVE +%token CONDITIONAL + + +%type <name> declarative +%type <name> verb_phrase +%type <name> noun_phrase +%type <name> position_phrase +%type <name> adverb + +%type <name> POSITIONAL VERB ADVERB PROPER_NOUN +%type <name> NOUN DECLARATIVE CONDITIONAL + +%% + +sentence_list : sentence + | sentence_list NEWLINE sentence + ; + + +sentence : verb_phrase noun_phrase position_phrase adverb period + { + printf("I understand that sentence.\n"); + printf("VP = %s \n",$1); + printf("NP = %s \n",$2); + printf("PP = %s \n",$3); + printf("AD = %s \n",$4); + } + | { yyerror("That's a strange sentence !!"); } + ; + +position_phrase : POSITIONAL declarative PROPER_NOUN + { + sprintf($$,"%s %s %s",$1,$2,$3); + } + | /* empty */ { strcpy($$,""); } + ; + + +verb_phrase : VERB { strcpy($$,$1); strcat($$," "); } + | adverb VERB + { + sprintf($$,"%s %s",$1,$2); + } + ; + +adverb : ADVERB { strcpy($$,$1); } + | /* empty */ { strcpy($$,""); } + ; + +noun_phrase : DECLARATIVE NOUN + { + sprintf($$,"%s %s",$1,$2); + } + | CONDITIONAL declarative NOUN + { + sprintf($$,"%s %s %s",$1,$2,$3); + } + | NOUN { strcpy($$,$1); strcat($$," "); } + ; + +declarative : DECLARATIVE { strcpy($$,$1); } + | /* empty */ { strcpy($$,""); } + ; + +period : /* empty */ + | PERIOD + ; + + +%% + +/* Supplied main() and yyerror() functions. */ + +int main(int argc, char *argv[]) +{ + yyparse(); /* parse the file */ + return(0); +} + +int yyerror(char *message) +{ + extern FILE *yyout; + + fprintf(yyout,"\nError at line %5d. (%s) \n", + yylexlinenum,message); +} |