gistfile1.c

%union {
	double dbl;
	char *text;
}

%token <text> tLPAREN tRPAREN      /* () */
%token <text> tLBRACE tRBRACE      /* {} */
%token <text> tLBRACKET tRBRACKET  /* {} */
%token <text> tPIPE                /* | */
%token <text> tCOLON               /* : */
%token <text> tSEMICOLON           /* ; */
%token <text> tDOT                 /* . */
%token <text> tCOMMA               /* , */
%token <text> tASSIGN              /* = */
%token <text> tARROW               /* -> */
%token <dbl> tNUMBER               /* <number> */
%token <text> tSTRING              /* Contents of a quoted string */
%token <text> tIDENTIFIER          /* An identifier, non quoted string matching [a-zA-Z0-9_]+ */

%type<text> variable assignment expression lhs object_access literal object
%start expressions

%{
	#include <stdio.h>
	#include <stdlib.h>
	extern int yylineno;
	extern char* yytext;
%}

%%
assignment:
	  lhs tASSIGN expression  { printf("------ %s = %s\n", $1, $3); $$=malloc(128); sprintf($$, "%s=%s", $1, $3); }
	;

lhs:
	  variable
	| object_access
	;

variable:
	  tIDENTIFIER { printf("variable: %s\n", $1); $$=malloc(128); sprintf($$, "%s", $1); }
	;

expressions:
	| expressions expression
	;
expression: { $$ = "expr"; }
	  object { printf("object!\n"); }
	| block { printf("Block!\n"); }
	| call { printf("Call!\n"); }
	| assignment
	| object_access
	| variable
	| literal
	| tLPAREN expression tRPAREN
	;

/* Block definition */
block:
	  tLBRACE block_args tPIPE expressions tRBRACE
	| tLBRACE tPIPE expressions tRBRACE
	| tLBRACE expressions tRBRACE
	;
block_args:
	  tCOLON block_arg
	| block_args tCOLON block_arg
	| block_args block_arg_identifier tCOLON block_arg
	;
block_arg:
	  tIDENTIFIER { printf("arg var: %s\n", $1); }
	;
block_arg_identifier:
	  tIDENTIFIER { printf("arg name: %s\n", $1); }
	;

/* Block call */
call:
	  lhs tDOT
	| lhs block_args tDOT
	;


/* Object definition */
object:
	  tLBRACKET object_members  tRBRACKET
	;
object_members:
	| object_members object_member
	;
object_member:
	  tIDENTIFIER tARROW expression { printf("object member: %s\n", $1); }
	;

/* Object access */
object_access:
	  variable tDOT tIDENTIFIER { printf("objectacc: %s.%s\n", $1, $3); $$=malloc(128); sprintf($$, "%s.%s", $1, $3); }
	;

literal:
	  tNUMBER  { printf("num %f\n", $1); $$=malloc(128); sprintf($$, "%f", $1); }
	| tSTRING  { printf("str '%s'\n", $1); }
	;

%%

int yyerror(char *str)
{
	fprintf(stderr, "%d: error: '%s' at '%s'\n", yylineno, str, yytext);

	exit(3);
	return 0;
}

int yywrap(void) {
	return 1;
}

int main()
{
	yydebug = 5;
	yyparse();
	return 0;
}