From f5835d85e2ae098aacb3f585bc63bea5c9e7884f Mon Sep 17 00:00:00 2001
From: Jussi Pakkanen <jpakkane@gmail.com>
Date: Fri, 25 Jan 2013 21:59:53 +0200
Subject: [PATCH] Added comparison.

---
 interpreter.py                       | 28 ++++++++++++++++++++---
 nodes.py                             | 20 +++++++++++++++--
 parser.py                            |  9 ++++++++
 test cases/19 comparison/builder.txt | 33 ++++++++++++++++++++++++++++
 test cases/19 comparison/prog.c      |  1 +
 5 files changed, 86 insertions(+), 5 deletions(-)
 create mode 100644 test cases/19 comparison/builder.txt
 create mode 100644 test cases/19 comparison/prog.c

diff --git a/interpreter.py b/interpreter.py
index 6b229b885..db570c7e0 100755
--- a/interpreter.py
+++ b/interpreter.py
@@ -284,6 +284,8 @@ class Interpreter():
             if varname in self.variables:
                 return self.variables[varname]
             raise InvalidCode('Line %d: unknown variable "%s".' % (cur.lineno(), varname))
+        elif isinstance(cur, nodes.Comparison):
+            return self.evaluate_comparison(cur)
         else:
             raise InvalidCode("Line %d: Unknown statement." % cur.lineno())
 
@@ -445,7 +447,7 @@ class Interpreter():
                     raise InvalidCode('Line %d: variable "%s" is not set' % (arg.lineno(), arg.value))
                 r = self.variables[arg.value]
             elif isinstance(arg, nodes.StringExpression) or isinstance(arg, nodes.StringStatement):
-                r = arg.get_string()
+                r = arg.get_value()
             elif isinstance(arg, nodes.FunctionCall):
                 r  = self.function_call(arg)
             elif isinstance(arg, nodes.MethodCall):
@@ -469,15 +471,35 @@ class Interpreter():
     
     def evaluate_if(self, node):
         result = self.evaluate_statement(node.get_clause())
+        cond = None
         if isinstance(result, nodes.BoolExpression) or \
            isinstance(result, nodes.BoolStatement):
-            if result.get_value():
+            cond = result.get_value()
+        if isinstance(result, bool):
+            cond = result
+        
+        if cond is not None:
+            if cond:
                 self.evaluate_codeblock(node.get_trueblock())
             else:
                 self.evaluate_codeblock(node.get_falseblock())
         else:
+            print(node.get_clause())
+            print(result)
             raise InvalidCode('Line %d: If clause does not evaluate to true or false.' % node.lineno())
-
+        
+    def evaluate_comparison(self, node):
+        v1 = self.evaluate_statement(node.get_first())
+        v2 = self.evaluate_statement(node.get_second())
+        val1 = v1.get_value()
+        val2 = v2.get_value()
+        assert(type(val1) == type(val2))
+        if node.get_ctype() == '==':
+            return val1 == val2
+        elif node.get_ctype() == '!=':
+            return val1 != val2
+        else:
+            raise InvalidCode('You broke me.')
 if __name__ == '__main__':
     code = """project('myawesomeproject')
     message('I can haz text printed out?')
diff --git a/nodes.py b/nodes.py
index b87022e4c..da2ab6c22 100644
--- a/nodes.py
+++ b/nodes.py
@@ -83,13 +83,29 @@ class IfStatement(Statement):
     def get_falseblock(self):
         return self.falseblock
 
+class Comparison(Statement):
+    def __init__(self, first, ctype, second, lineno):
+        Statement.__init__(self, lineno)
+        self.first = first
+        self.ctype = ctype
+        self.second = second
+    
+    def get_first(self):
+        return self.first
+
+    def get_ctype(self):
+        return self.ctype
+
+    def get_second(self):
+        return self.second
+
 class StringStatement(Statement):
     def __init__(self, value, lineno):
         assert(type(value) == type(''))
         Statement.__init__(self, lineno)
         self.value = value
-        
-    def get_string(self):
+
+    def get_value(self):
         return self.value
 
 class FunctionCall(Statement):
diff --git a/parser.py b/parser.py
index 96cf1f741..ad2e87f62 100755
--- a/parser.py
+++ b/parser.py
@@ -34,6 +34,8 @@ tokens = ['LPAREN',
           'ATOM',
           'COMMENT',
           'ASSIGN',
+          'EQUALS',
+          'NEQUALS',
           'COMMA',
           'DOT',
           'STRING',
@@ -42,6 +44,8 @@ tokens = ['LPAREN',
           ] + list(reserved.values())
 
 t_ASSIGN = '='
+t_EQUALS = '=='
+t_NEQUALS = '\!='
 t_LPAREN = '\('
 t_RPAREN = '\)'
 t_LBRACKET = '\['
@@ -115,6 +119,11 @@ def p_statement_assign(t):
     'statement : expression ASSIGN statement'
     t[0] = nodes.Assignment(t[1], t[3], t.lineno(1))
 
+def p_statement_equals(t):
+    '''statement : statement EQUALS statement
+                 | statement NEQUALS statement'''
+    t[0] = nodes.Comparison(t[1], t[2], t[3], t.lineno(1))
+
 def p_statement_func_call(t):
     'statement : expression LPAREN args RPAREN'
     t[0] = nodes.FunctionCall(t[1], t[3], t.lineno(1))
diff --git a/test cases/19 comparison/builder.txt b/test cases/19 comparison/builder.txt
new file mode 100644
index 000000000..4c84fda29
--- /dev/null
+++ b/test cases/19 comparison/builder.txt	
@@ -0,0 +1,33 @@
+project('comparison', 'c')
+
+var1 = 'foo'
+var2 = 'bar'
+
+if(var1 == var2)
+  exe1 = executable('broken', 'broken.c')
+else
+  exe1 = executable('prog1', 'prog.c')
+endif
+
+if(var1 == var1)
+  exe2 = executable('prog2', 'prog.c')
+else
+  exe2 = executable('broken', 'broken.c')
+endif
+
+if(var1 != var2)
+  exe3 = executable('prog3', 'prog.c')
+else
+  exe3 = executable('broken', 'broken.c')
+endif
+
+if(var1 != var1)
+  exe4 = executable('broken', 'broken.c')
+else
+  exe4 = executable('prog4', 'prog.c')
+endif
+
+add_test('equalfalse', exe1)
+add_test('equaltrue', exe2)
+add_test('nequaltrue', exe3)
+add_test('nequalfalse', exe4)
diff --git a/test cases/19 comparison/prog.c b/test cases/19 comparison/prog.c
new file mode 100644
index 000000000..0314ff17b
--- /dev/null
+++ b/test cases/19 comparison/prog.c	
@@ -0,0 +1 @@
+int main(int argc, char **argv) { return 0; }