From d64ba3eaacfc75bcdf91bca939ebb2ac125cbaf4 Mon Sep 17 00:00:00 2001
From: Yohann D'ANELLO <yohann.danello@gmail.com>
Date: Sat, 16 May 2020 02:59:03 +0200
Subject: [PATCH] If/then/else clauses

---
 syntaxique/lang.y    | 12 +++++++++++-
 syntaxique/langlex.l |  4 ++++
 syntaxique/test.my   | 29 ++++++++++++++++++++++++-----
 3 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/syntaxique/lang.y b/syntaxique/lang.y
index c6b9dfc..386fde6 100644
--- a/syntaxique/lang.y
+++ b/syntaxique/lang.y
@@ -122,7 +122,7 @@ stmt* make_stmt (int type, var *var, expr *expr,
 %type <e> expr
 %type <s> stmt assign
 
-%token BOOL WHILE DO OD ASSIGN PRINT OR AND XOR NOT TRUE FALSE
+%token BOOL WHILE DO OD IF THEN ELSE FI ASSIGN PRINT OR AND XOR NOT TRUE FALSE
 %token <i> IDENT
 
 %left ';'
@@ -146,6 +146,10 @@ stmt	: assign
 		{ $$ = make_stmt(';',NULL,NULL,$1,$3,NULL); }
 	| WHILE expr DO stmt OD
 		{ $$ = make_stmt(WHILE,NULL,$2,$4,NULL,NULL); }
+	| IF expr THEN stmt ELSE stmt FI
+		{ $$ = make_stmt(IF,NULL,$2,$4,$6,NULL); }
+	| IF expr THEN stmt FI
+		{ $$ = make_stmt(IF,NULL,$2,$4,NULL,NULL); }
 	| PRINT varlist
 		{ $$ = make_stmt(PRINT,NULL,NULL,NULL,NULL,$2); }
 
@@ -216,6 +220,12 @@ void execute (stmt *s)
 		case WHILE:
 			while (eval(s->expr)) execute(s->left);
 			break;
+		case IF:
+			if (eval(s->expr))
+				execute(s->left);
+			else if (s->right != NULL)
+				execute(s->right);
+			break;
 		case PRINT: 
 			print_vars(s->list);
 			puts("");
diff --git a/syntaxique/langlex.l b/syntaxique/langlex.l
index bcea3eb..09a51bc 100644
--- a/syntaxique/langlex.l
+++ b/syntaxique/langlex.l
@@ -8,6 +8,10 @@ DIG	[0-9]
 "while"	{ return WHILE; }
 "do"	{ return DO; }
 "od"	{ return OD; }
+"if"	{ return IF; }
+"then"	{ return THEN; }
+"fi"	{ return FI; }
+"else"	{ return ELSE; }
 "print"	{ return PRINT; }
 "true"	{ return TRUE; }
 "false"	{ return FALSE; }
diff --git a/syntaxique/test.my b/syntaxique/test.my
index 0f41a24..e19b089 100644
--- a/syntaxique/test.my
+++ b/syntaxique/test.my
@@ -2,20 +2,39 @@ bool x,y,z;
 
 x := true;
 y := true;
-z := x <=> y;
-print x,y,z;
+if x <=> y then
+	z := x && y;
+	print x,y,z
+else
+	print y,x,z
+fi;
 
 x := true;
 y := false;
 z := x <=> y;
-print x,y,z;
+if x <=> y then
+	z := x && y;
+	print x,y,z
+else
+	print y,x,z
+fi;
 
 x := false;
 y := true;
 z := x <=> y;
-print x,y,z;
+if x <=> y then
+	z := x && y;
+	print x,y,z
+else
+	print y,x,z
+fi;
 
 x := false;
 y := false;
 z := x <=> y;
-print x,y,z
+if x <=> y then
+	z := x && y;
+	print x,y,z
+else
+	print y,x,z
+fi