From d2baa4a3c0d634ad154abae3287d0c9680f8d079 Mon Sep 17 00:00:00 2001
From: Pedro <pedroflemming@gmail.com>
Date: Wed, 22 Oct 2014 16:01:25 +0200
Subject: [PATCH] now using tokens to describe predicate type instead of string

---
 src/bison/SQLParser.h    |  1 +
 src/bison/bison_parser.y | 15 ++++++++++-----
 src/bison/flex_lexer.l   | 40 +++++++++++++++++++---------------------
 src/lib/Expr.cpp         |  5 +++--
 src/lib/Expr.h           |  5 +++--
 src/sql_tests.cpp        |  4 ++--
 6 files changed, 38 insertions(+), 32 deletions(-)

diff --git a/src/bison/SQLParser.h b/src/bison/SQLParser.h
index 779a644..c82c54d 100644
--- a/src/bison/SQLParser.h
+++ b/src/bison/SQLParser.h
@@ -2,6 +2,7 @@
 #define __SQLPARSER_H_
 
 #include "Statement.h"
+#include "bison_parser.h"
 
 class SQLParser {
 public:
diff --git a/src/bison/bison_parser.y b/src/bison/bison_parser.y
index 5ce8054..2422b34 100644
--- a/src/bison/bison_parser.y
+++ b/src/bison/bison_parser.y
@@ -61,6 +61,7 @@ typedef void* yyscan_t;
  *********************************/
 %union {
 	float number;
+	uint uintnum;
 	char* sval;
 
 	Statement* statement;
@@ -79,9 +80,8 @@ typedef void* yyscan_t;
  *********************************/
 %token SELECT FROM GROUP BY WHERE NOT AND OR
 %token <sval> NAME STRING COMPARISON
-%token <number> INTNUM
-
-
+%token <number> FLOAT
+%token <uintnum> EQUALS NOTEQUALS LESS GREATER LESSEQ GREATEREQ
 
 /*********************************
  ** Non-Terminal types (http://www.gnu.org/software/bison/manual/html_node/Type-Decl.html)
@@ -182,7 +182,12 @@ predicate:
 
 
 comparison_predicate:
-		scalar_exp COMPARISON scalar_exp { $$ = makePredicate($1, $2, $3); }
+		scalar_exp EQUALS scalar_exp { $$ = makePredicate($1, EQUALS, $3); }
+	|	scalar_exp NOTEQUALS scalar_exp { $$ = makePredicate($1, NOTEQUALS, $3); }
+	|	scalar_exp LESS scalar_exp { $$ = makePredicate($1, LESS, $3); }
+	|	scalar_exp GREATER scalar_exp { $$ = makePredicate($1, GREATER, $3); }
+	|	scalar_exp LESSEQ scalar_exp { $$ = makePredicate($1, LESSEQ, $3); }
+	|	scalar_exp GREATEREQ scalar_exp { $$ = makePredicate($1, GREATEREQ, $3); }
 	;
 
 // TODO: Expression can also be scalar_exp
@@ -209,7 +214,7 @@ table_name:
 
 literal:
 		STRING { $$ = makeStringLiteral($1); }
-	|	INTNUM { $$ = makeFloatLiteral($1); }
+	|	FLOAT { $$ = makeFloatLiteral($1); }
 	;
 
 
diff --git a/src/bison/flex_lexer.l b/src/bison/flex_lexer.l
index 96c7081..80bf361 100644
--- a/src/bison/flex_lexer.l
+++ b/src/bison/flex_lexer.l
@@ -15,7 +15,7 @@
 #include "bison_parser.h"
 #include <stdio.h>
 
-#define TOK(name) { return name; }
+#define TOKEN(name) { return name; }
 
 %}
 /***************************
@@ -46,36 +46,34 @@
 
 [ \t\n]+	/* skip whitespace */;
 
-SELECT	TOK(SELECT)
-FROM	TOK(FROM)
-GROUP	TOK(GROUP)
-BY		TOK(BY)
-WHERE	TOK(WHERE)
-NOT		TOK(NOT)
-AND		TOK(AND)
-OR		TOK(OR)
+SELECT	TOKEN(SELECT)
+FROM	TOKEN(FROM)
+GROUP	TOKEN(GROUP)
+BY		TOKEN(BY)
+WHERE	TOKEN(WHERE)
+NOT		TOKEN(NOT)
+AND		TOKEN(AND)
+OR		TOKEN(OR)
+
+"="		TOKEN(EQUALS)
+"<>" 	TOKEN(NOTEQUALS)
+"<"		TOKEN(LESS)
+">"		TOKEN(GREATER)
+"<="	TOKEN(LESSEQ)
+">="	TOKEN(GREATEREQ)
 
 
-"="		|
-"<>" 	|
-"<"		|
-">"		|
-"<="	|
-">="	{
-	yylval->sval = strdup(yytext);
-	return COMPARISON;
-}
+[-+*/(),.;]	TOKEN(yytext[0])
 
 
-[-+*/(),.;]	TOK(yytext[0])
-
 [0-9]+	|
 [0-9]+"."[0-9]* |
 "."[0-9]*	{
 	yylval->number = atof(yytext);
-	return INTNUM;
+	return FLOAT;
 }
 
+
 [A-Za-z][A-Za-z0-9_]* {
 	yylval->sval = strdup(yytext);
 	return NAME;
diff --git a/src/lib/Expr.cpp b/src/lib/Expr.cpp
index 05d9ab5..dcca445 100644
--- a/src/lib/Expr.cpp
+++ b/src/lib/Expr.cpp
@@ -15,9 +15,10 @@ Expr* makeFunctionRef(char* func_name, Expr* expr) {
 	return e;
 }
 
-Expr* makePredicate(Expr* expr1, char* op, Expr* expr2) {
+Expr* makePredicate(Expr* expr1, uint op, Expr* expr2) {
 	ALLOC_EXPR(e, eExprPredicate);
-	e->name = op;
+	// printf("Pred: %u\n", op);
+	e->pred_type = op;
 	e->expr = expr1;
 	e->expr2 = expr2;
 	return e;
diff --git a/src/lib/Expr.h b/src/lib/Expr.h
index dc3f812..99d6c5e 100644
--- a/src/lib/Expr.h
+++ b/src/lib/Expr.h
@@ -17,9 +17,10 @@ typedef struct Expr Expr;
 struct Expr {
 	EExprType type;
 
-	char* name;
 	Expr* expr;
 	Expr* expr2;
+	char* name;
+	uint pred_type;
 	float float_literal;
 };
 
@@ -36,7 +37,7 @@ struct Expr {
 
 Expr* makeColumnRef(char* name);
 Expr* makeFunctionRef(char* func_name, Expr* expr);
-Expr* makePredicate(Expr* expr1, char* op, Expr* expr2);
+Expr* makePredicate(Expr* expr1, uint op, Expr* expr2);
 Expr* makeFloatLiteral(float value);
 Expr* makeStringLiteral(char* string);
 
diff --git a/src/sql_tests.cpp b/src/sql_tests.cpp
index 247d285..f2ef14d 100644
--- a/src/sql_tests.cpp
+++ b/src/sql_tests.cpp
@@ -18,7 +18,7 @@ void SelectTest1() {
 	printf("Test: SelectTest1... ");
 	fflush(stdout);
 
-	const char* sql = "SELECT age, name, address from table WHERE age > 12.5;";
+	const char* sql = "SELECT age, name, address from table WHERE age < 12.5;";
 	Statement* sqlStatement = SQLParser::parseSQL(sql);
 	ASSERT(sqlStatement != NULL);
 	ASSERT(sqlStatement->type == eSelect);
@@ -38,7 +38,7 @@ void SelectTest1() {
 	ASSERT(stmt->where_clause != NULL);
 	ASSERT(stmt->where_clause->expr->type == eExprColumnRef);
 	ASSERT_STR(stmt->where_clause->expr->name, "age");
-	ASSERT_STR(stmt->where_clause->name, ">");
+	ASSERT(stmt->where_clause->pred_type == LESS);
 	ASSERT(stmt->where_clause->expr2->type == eExprLiteralFloat);
 	ASSERT(stmt->where_clause->expr2->float_literal == 12.5);