/*
 *  Laboration 2 i C och UNIX
 *
 *  Komplett shell
 *  =========================================
 *
 *  Christian Ohlsson, di7chro@cse.kau.se
 *  Stefan Sonesson, di7stes@cse.kau.se
 *
 *  Karlstads Universitet, 991209
 *
 *
 *===========================================
*/
%{
#include <stdio.h>
#include "tree.h"
	extern treePtr tree;
%}

%union {
	int txt;
	treePtr tPtr;
};

%token NL PIPE SEMI GREAT LESS AND DBLARR EXIT
%token<txt> WORD OPT
%type<tPtr> rad ccmd scmd cmd

%start rad

%%
rad	: ccmd NL		{ tree=$1; return 0;}
	| NL			{ return 1;}            	
	;
ccmd	: ccmd PIPE scmd	{ $$=(treePtr)makeNode(PIPE, $1, $3); }
	| ccmd AND 		{ $$=(treePtr)makeNode(AND, $1, NULL); }
	| ccmd SEMI scmd	{ $$=(treePtr)makeNode(SEMI, $1, $3); }
	| ccmd SEMI 		{ $$=(treePtr)makeNode(SEMI, $1, NULL);}
	| scmd			{ $$=$1;}
	;
scmd	: scmd GREAT WORD	{ $$=(treePtr)makeNode(GREAT, $1, makeLeaf($3));}
	| scmd DBLARR WORD	{ $$=(treePtr)makeNode(DBLARR, $1, makeLeaf($3));}
	| scmd LESS WORD	{ $$=(treePtr)makeNode(LESS, $1, makeLeaf($3));}
	| cmd			{ $$=$1;}
	| error			{ $$=NULL;}
	;
cmd	: cmd WORD		{ $$=$1;}
	| WORD			{ $$=(treePtr)makeLeaf($1);}
	;
%%

int yyerror() {
	fprintf(stderr, "\nSyntax error\n");
	tree=NULL;
	return 0;
}