Create if-else expression

smnp/ast/node/condition.py

@@ -0,0 +1,42 @@
+from smnp.ast.node.model import Node
+from smnp.ast.node.none import NoneNode
+
+
+class IfElse(Node):
+    def __init__(self, pos):
+        super().__init__(pos)
+        self.children = [NoneNode(), NoneNode(), NoneNode()]
+
+    @property
+    def condition(self):
+        return self[0]
+
+    @condition.setter
+    def condition(self, value):
+        self[0] = value
+
+    @property
+    def ifNode(self):
+        return self[1]
+
+    @ifNode.setter
+    def ifNode(self, value):
+        self[1] = value
+
+    @property
+    def elseNode(self):
+        return self[2]
+
+    @elseNode.setter
+    def elseNode(self, value):
+        self[2] = value
+
+    @classmethod
+    def createNode(cls, ifNode, condition, elseNode=NoneNode()):
+        node = cls(ifNode.pos)
+        node.ifNode = ifNode
+        node.condition = condition
+        node.elseNode = elseNode
+        return node
+
+

smnp/ast/node/expression.py

@@ -1,3 +1,4 @@
+from smnp.ast.node.condition import IfElse
 from smnp.ast.node.operator import BinaryOperator
 from smnp.ast.node.term import TermParser
 from smnp.ast.node.valuable import Valuable
@@ -8,17 +9,56 @@ from smnp.token.type import TokenType
 class Expression(Valuable):
     pass
 
-ExpressionParser = Parser.leftAssociativeOperatorParser(TermParser, [TokenType.PLUS, TokenType.MINUS], TermParser,
-                                                        lambda left, op, right: Expression.withValue(BinaryOperator.withValues(left, op, right)))
 
-Expression2Parser = Parser.leftAssociativeOperatorParser(ExpressionParser, [TokenType.RELATION], ExpressionParser,
-                                                         lambda left, op, right: Expression.withValue(BinaryOperator.withValues(left, op, right)))
+def ExpressionParser(input):
+    return Parser.leftAssociativeOperatorParser(
+        TermParser,
+        [TokenType.PLUS, TokenType.MINUS],
+        TermParser,
+        lambda left, op, right: Expression.withValue(BinaryOperator.withValues(left, op, right))
+    )(input)
 
-Expression3Parser = Parser.leftAssociativeOperatorParser(Expression2Parser, [TokenType.AND], Expression2Parser,
-                                                         lambda left, op, right: Expression.withValue(BinaryOperator.withValues(left, op, right)))
 
-Expression4Parser = Parser.leftAssociativeOperatorParser(Expression3Parser, [TokenType.OR], Expression3Parser,
-                                                         lambda left, op, right: Expression.withValue(BinaryOperator.withValues(left, op, right)))
+def Expression2Parser(input):
+    return Parser.leftAssociativeOperatorParser(
+        ExpressionParser,
+        [TokenType.RELATION],
+        ExpressionParser,
+        lambda left, op, right: Expression.withValue(BinaryOperator.withValues(left, op, right))
+    )(input)
+
+
+def Expression3Parser(input):
+    return Parser.leftAssociativeOperatorParser(
+        Expression2Parser,
+        [TokenType.AND],
+        Expression2Parser,
+        lambda left, op, right: Expression.withValue(BinaryOperator.withValues(left, op, right))
+    )(input)
+
+
+def Expression4Parser(input):
+    exprParser = Parser.leftAssociativeOperatorParser(
+        Expression3Parser,
+        [TokenType.OR],
+        Expression3Parser,
+        lambda left, op, right: Expression.withValue(BinaryOperator.withValues(left, op, right))
+    )
+
+    ifElseExpression = Parser.allOf(
+        exprParser,
+        Parser.terminalParser(TokenType.IF),
+        Expression4Parser,
+        Parser.terminalParser(TokenType.ELSE),
+        Expression4Parser,
+        createNode=lambda ifNode, _, condition, __, elseNode: IfElse.createNode(ifNode, condition, elseNode)
+    )
+
+    return Parser.oneOf(
+        ifElseExpression,
+        exprParser,
+    )(input)
+
 
 MaxPrecedenceExpressionParser = Expression4Parser
 

smnp/token/tokenizer.py

@@ -51,9 +51,11 @@ tokenizers = (
     separated(defaultTokenizer(TokenType.EXTEND)),
     separated(defaultTokenizer(TokenType.IMPORT)),
     separated(defaultTokenizer(TokenType.FROM)),
+    separated(defaultTokenizer(TokenType.ELSE)),
     separated(defaultTokenizer(TokenType.AND)),
     separated(defaultTokenizer(TokenType.NOT)),
     separated(defaultTokenizer(TokenType.AS)),
+    separated(defaultTokenizer(TokenType.IF)),
     separated(defaultTokenizer(TokenType.OR)),
 
     # Identifier (couldn't be before keywords!)

smnp/token/type.py

@@ -36,6 +36,8 @@ class TokenType(Enum):
     EXTEND = 'extend'
     IMPORT = 'import'
     FROM = 'from'
+    ELSE = 'else'
+    IF = 'if'
     AS = 'as'
     IDENTIFIER = 'identifier'
     COMMENT = 'comment'