for-count implementation

2 files changed, 17 insertions, 0 deletions

diff --git a/interpreter.py b/interpreter.py
index f252bc9..6a88c57 100644
--- a/interpreter.py
+++ b/interpreter.py
@@ -263,6 +263,21 @@ def interpretToString(expr, env):
 
 GLOBALS.register("->string", Builtin(interpretToString, 1))
 
+def interpretForCount(expr, env):
+    # for-count int exprs
+    num = evaluate(expr.args[0], env)
+    if type(num) is not int:
+        raise Exception("'for-count' count must be an integer")
+    new_env = Environment(env)
+    ret = None
+    for idx in range(0, num):
+        new_env.register("idx", Expr.Literal(idx + 1))
+        for arg in expr.args[1:]:
+            ret = evaluate(arg, new_env)
+    return ret
+
+GLOBALS.register("for-count", Builtin(interpretForCount))
+
 def interpretEnv(expr, env_expr, env):
     ev = evaluate(env_expr, env)
     return ev  # TODO more than this?
diff --git a/lexer.py b/lexer.py
index 5be76c6..e98972f 100644
--- a/lexer.py
+++ b/lexer.py
@@ -45,6 +45,7 @@ class TokenType(Enum):
 
     # flow
     IF = auto()
+    FOR_COUNT = auto()
 
     # keywords
     DEF = auto()
@@ -68,6 +69,7 @@ keywords = {
     "and": TokenType.AND,
     "or": TokenType.OR,
     "if": TokenType.IF,
+    "for-count": TokenType.FOR_COUNT,
     "def": TokenType.DEF,
     "lambda": TokenType.LAMBDA }