implement print statement

4 files changed, 22 insertions, 1 deletions

diff --git a/src/front/ast.py b/src/front/ast.py
index 77aab95..f272ca2 100644
--- a/src/front/ast.py
+++ b/src/front/ast.py
@@ -149,6 +149,18 @@ class ReturnStatement(Statement):
     def __repr__(self):
         return "<ReturnStatement at line %d>" % self.lineno
 
+class PrintStatement(Statement):
+    def __init__(self, expression, lineno = -1):
+        self.expression = expression
+        self.lineno = lineno
+
+    def generate(self, before, after, last):
+        self.debug("PrintStatement.generate(before = %d, after = %d): %s" % (before, after, repr(self)))
+        self.emit(Op.PRINT, self.expression.reduce(), last)
+
+    def __repr__(self):
+        return "<PrintStatement at line %d>" % self.lineno
+
 class AssignStatement(Statement):
     def __init__(self, ident, expression, lineno = -1):
         self.ident = ident
diff --git a/src/front/lexer.py b/src/front/lexer.py
index e6eb172..dcaa672 100644
--- a/src/front/lexer.py
+++ b/src/front/lexer.py
@@ -22,6 +22,7 @@ class Lexer:
                               'if': Token(Tag.IF),
                               'else': Token(Tag.ELSE),
                               'call': Token(Tag.CALL),
+                              'print': Token(Tag.PRINT),
                               'fun': Token(Tag.FUN),
                               'end': Token(Tag.END)}
         return
diff --git a/src/front/parser.py b/src/front/parser.py
index 72e0051..5029158 100644
--- a/src/front/parser.py
+++ b/src/front/parser.py
@@ -149,12 +149,13 @@ class Parser:
         self.match(Tag.END, Tag.NEWLINE)
         return Function(name, args, block, line)
 
-    # statement = ( if_statement | while_statement | assign_statement | return_statement | function_call ) nl.
+    # statement = ( if_statement | while_statement | assign_statement | return_statement | function_call | print_statement ) nl.
     def statement(self):
         res =  {Tag.IF:         self.if_statement,
                 Tag.WHILE:      self.while_statement,
                 Tag.IDENT:      self.assignment,
                 Tag.RETURN:     self.return_statement,
+                Tag.PRINT:      self.print_statement,
                 Tag.CALL:       self.function_call,
                 }[self.token.tag]()
         self.match(Tag.NEWLINE)
@@ -201,6 +202,12 @@ class Parser:
         self.scope.add_locals(name)
         return AssignStatement(name, exp, line)
 
+    def print_statement(self):
+        line = self.lexer.line
+        self.match(Tag.PRINT)
+        exp = self.boolean()
+        return PrintStatement(exp, line)
+
     # program = function_list.
     def program(self):
         return Program(self.function_list())
diff --git a/src/front/token.py b/src/front/token.py
index 78e9dab..d0970f3 100644
--- a/src/front/token.py
+++ b/src/front/token.py
@@ -26,6 +26,7 @@ Tag.LPAREN      = Tag("LPAREN")
 Tag.RPAREN      = Tag("RPAREN")
 Tag.NEWLINE     = Tag("NEWLINE")
 Tag.COMMA       = Tag("COMMA")
+Tag.PRINT       = Tag("PRINT")
 Tag.FUN         = Tag("FUN")
 Tag.CALL        = Tag("CALL")
 Tag.ASSIGNMENT  = Tag("ASSIGNMENT")