refactor: only evaluate expressions as needed

1 files changed, 28 insertions, 9 deletions

diff --git a/tokens.py b/tokens.py
index 38e669c..cc8e7a7 100644
--- a/tokens.py
+++ b/tokens.py
@@ -40,10 +40,12 @@ class NebSeparator():
     pass
 
 class NebOpen(NebSeparator):
-    pass
+    def __str__(self):
+        return "("
 
 class NebClose(NebSeparator):
-    pass
+    def __str__(self):
+        return ")"
 
 class NebSymbol(NebToken):
 
@@ -51,21 +53,38 @@ class NebSymbol(NebToken):
         super().__init__(NebType.SYMBOL)
         self.name = name
 
+    def __str__(self):
+        return f"'{self.name}"
+
 class NebExpression(NebToken):
 
     def __init__(self, symbol, args):
         super().__init__(NebType.EXPR)
         self.symbol = symbol
         self.args = args
+        self.returns = None
+
+    def set_returns(self, returns):
+        self.returns = returns
 
-    def maybe_sig(self):
-        out = []
+    def __str__(self):
+        out = f"({self.symbol}"
         for arg in self.args:
-            if isinstance(arg, NebLiteral):
-                out.append(":" + arg.type_.name.lower())
-            else:
-                raise Exception("expressions must have a list of literals") #TODO not true
-        return " ".join(out)
+            out += f" {arg}"
+        out += f") <{self.type_}> -> <{self.out_sig()}>"
+        return out
+
+    def in_sig(self):
+        return " ".join(f":{arg.type_.name.lower()}" for arg in self.args)
+
+    def out_sig(self):
+        if self.returns is None:
+            return "?"
+        else:
+            return ":" + self.returns.lower()
+
+    def sig(self):
+        return (self.in_sig() + " > " + self.out_sig()).strip()
 
 class NebFunction():