Add if else and rename (_|_) -> (_Y_).

Signed-off-by: Slendi <[email protected]>

src/ast.rs

@@ -10,6 +10,7 @@ pub enum Node {
 
     VarSet(String, Box<Node>),
     While(Box<Node>, Box<Node>),
+    IfElse(Box<Node>, Box<Node>, Option<Box<Node>>),
 }
 
 impl Debug for Node {
@@ -24,6 +25,7 @@ impl Debug for Node {
             Block(v) => write!(fmt, "Block{:?}", v),
             VarSet(name, v) => write!(fmt, "{} = {:?}", name, v),
             While(v, block) => write!(fmt, "While({:?})->{:?}", v, block),
+            IfElse(a, b, c) => write!(fmt, "If({:?})->{:?}->{:?}", a, b, c),
         }
     }
 }

src/gp.lalrpop

@@ -12,7 +12,8 @@ List<T>: Vec<T> =
 Stmt = {
 	Block,
 	<Expr> "~~",
-	"(_|_)" <Expr> <Block> => Box::new(Node::While(<>)),
+	"(_Y_)" <Expr> <Block> => Box::new(Node::While(<>)),
+	"(.Y.)" <Expr> <Block> <(r"U+O+H+" <Block>)?> => Box::new(Node::IfElse(<>)),
 }
 
 Block: Box<Node> = {
@@ -72,6 +73,7 @@ Identifier = r"[a-zA-Z_][a-zA-Z0-9_]*";
 match {
 	r"[oO][wW][oO]",
 	r"[uU][wW][uU]",
+	r"U+O+H+",
 } else {
 	r"[a-zA-Z_][a-zA-Z0-9_]*",
 	_,

src/main.rs

@@ -20,6 +20,7 @@ enum Value {
     Integer(i64),
     String(String),
     Err,
+    None,
 }
 
 impl Value {
@@ -29,6 +30,7 @@ impl Value {
             Integer(x) => *x != 0,
             String(x) => x.len() != 0,
             Err => false,
+            None => false,
         }
     }
 }
@@ -40,6 +42,7 @@ impl Debug for Value {
             Integer(v) => write!(fmt, "{:?}", v),
             String(v) => write!(fmt, "{:?}", v),
             Err => write!(fmt, "Err"),
+            None => write!(fmt, "None"),
         }
     }
 }
@@ -100,6 +103,17 @@ impl ast::Node {
                 }
                 last_result
             }
+            IfElse(expr, real, fake) => {
+                if expr.interpret(vars).is_truthy() {
+                    real.interpret(vars)
+                } else {
+                    if let Some(x) = fake {
+                        x.interpret(vars)
+                    } else {
+                        Value::None
+                    }
+                }
+            }
         }
     }
 }

test.gpl

@@ -9,7 +9,7 @@ a :3 8==D~~
 
 "Create a sum"
 sum >///< 8D~~
-(_|_) a Nya!
+(_Y_) a Nya!
 	sum >///< sum :3 8==D~~
 	a >///< a >:3 8=D~~
 nya~