nested expressions!

1 files changed, 12 insertions, 5 deletions

diff --git a/parser.py b/parser.py
index 6360b62..97717bf 100644
--- a/parser.py
+++ b/parser.py
@@ -7,19 +7,26 @@ def peek(inp):
     return inp[0]
 
 def parse_expression(tkns):
-    # expressions MUST start with a symbol (for now?)
     symbol = None
     args = []
+    add_idx = 0
     for idx, t in enumerate(tkns):
-        #if isinstance(t, NebOpen):
+        # if we evaluated a nested expression, skip ahead
+        if add_idx > 0:
+            add_idx -= 1
+            continue
         if idx == 0:
             if not isinstance(t, NebSymbol):
                 raise Exception("expressions must start with a symbol")
             else:
                 symbol = t
         elif isinstance(t, NebClose):
-            return NebExpression(symbol, args), tkns[idx + 1:]
-        else:  # TODO nested expressions
+            return NebExpression(symbol, args), tkns[idx + 1:], idx + 1
+        # nested expressions
+        elif isinstance(t, NebOpen):
+            expr, remainder, add_idx = parse_expression(tkns[idx + 1:])
+            args.append(expr)
+        else:
             args.append(t)
             
     raise Exception("couldn't parse expression!")
@@ -29,7 +36,7 @@ def parse(tkns, parsed):
     if nxt is None:
         return parsed
     if isinstance(nxt, NebOpen):
-        expr, remainder = parse_expression(tkns[1:])
+        expr, remainder, _ = parse_expression(tkns[1:])
         parsed.append(expr)
         return parse(remainder, parsed)
     elif isinstance(nxt, NebLiteral):