From 832fdc34f62648eef7f0fa7bb57e510ba08460e9 Mon Sep 17 00:00:00 2001
From: Brandon Rozek <brozek@mail.umw.edu>
Date: Thu, 20 Sep 2018 21:42:59 -0400
Subject: [PATCH] Allows parser to recognize true/false in code. No logic has
 been written yet to handle it.

---
 src/lexer.l  |  2 ++
 src/node.h   |  1 +
 src/parser.y | 20 ++++++++++++++++++--
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/lexer.l b/src/lexer.l
index 6c6c927..cefd7d9 100644
--- a/src/lexer.l
+++ b/src/lexer.l
@@ -39,6 +39,8 @@ DIGIT [0-9]
 "while"                 {return WHILE;}
 "print"                 {return PRINT;}
 "input"                 {return INPUT;}
+"true"                  {yylval.value = make_node(BOOLEAN, make_value(LONG, 1, 0), ""); return ETRUE;}
+"false"                 {yylval.value = make_node(BOOLEAN, make_value(LONG, 0, 0), ""); return EFALSE;}
 {DIGIT}                 {yylval.value = make_node(VALUE, make_value(LONG, atoi(yytext), 0), ""); return VALUE;}
 {DIGIT}*"."?{DIGIT}+    {yylval.value = make_node(VALUE, make_value(DOUBLE, 0, atof(yytext)), ""); return VALUE;}
 [_a-zA-Z][_a-zA-Z0-9]*  {yylval.value = make_node(IDENTIFIER,  NULL, strdup(yytext)); return IDENTIFIER;}
diff --git a/src/node.h b/src/node.h
index 3b410cb..4338986 100644
--- a/src/node.h
+++ b/src/node.h
@@ -8,6 +8,7 @@
 
 #define DOUBLE 300
 #define LONG 301
+#define BOOLEAN 302
 
 // Share the line number between files
 extern int linenum;
diff --git a/src/parser.y b/src/parser.y
index c9e9db9..fdca7cf 100644
--- a/src/parser.y
+++ b/src/parser.y
@@ -51,6 +51,8 @@ struct Node* result;
 %token COMMENT            
 %token WHITESPACE   
 %token DONE
+%token <value> ETRUE
+%token <value> EFALSE
 
 /* declare non-terminals */
 %type <value> program statement assignment if-statement if-else-statement while print statements substatements expression subexpression term subterm factor atom identvalue ident
@@ -138,6 +140,8 @@ ident: IDENTIFIER { $$ = $1; }
 identvalue: IDENTIFIER { $$ = $1; }
           | VALUE { $$ = $1; }
           | INPUT { $$ = make_node(INPUT, NULL , ""); }
+          | ETRUE  { $$ = $1; }
+          | EFALSE { $$ = $1; }
 
 
 
@@ -246,7 +250,13 @@ void print_tree(struct Node* node, int tabs) {
     case INPUT: printf("INPUT:\n"); break;
     case STATEMENT: printf("STATEMENT:\n"); break;
     case VALUE: 
-      if (node->value->type == LONG) {
+      if (node->value->type == BOOLEAN) {
+        if (get_long(node->value)) {
+          printf("VALUE: true\n");
+        } else {
+          printf("VALUE: false\n");
+        }
+      } else if (node->value->type == LONG) {
         printf("VALUE: %li\n", get_long(node->value));
       } else { // Assume double
         printf("VALUE: %lf\n", get_double(node->value));
@@ -807,7 +817,13 @@ void eval_statement(struct Node* node, struct Environment* env) {
     case PRINT:
       check_num_nodes(node, 1, "can only print out one expression at a time.");
       tempVal = eval_expression(node->children[0], env);
-      if (tempVal->type == LONG) {
+      if (tempVal->type == BOOLEAN) { 
+        if (get_long(tempVal)) {
+          printf("true\n");
+        } else {
+          printf("false\n");
+        }
+      } else if (tempVal->type == LONG) {
         printf("%li\n", get_long(tempVal));
       } else {
         printf("%lf\n", get_double(tempVal));