implement reduce

1 files changed, 13 insertions, 1 deletions

diff --git a/neb/std/functools.py b/neb/std/functools.py
index f83c49d..8ef5630 100644
--- a/neb/std/functools.py
+++ b/neb/std/functools.py
@@ -1,4 +1,4 @@
-from .. import TypeEnum, Environment, Arg, Builtin, Function, evaluate, InterpretPanic
+from .. import TypeEnum, Environment, Arg, Builtin, Function, evaluate, InterpretPanic, NebSyntax
 from ..structs import *
 
 FUNCTOOLS = Environment()
@@ -42,3 +42,15 @@ def interpretApply(symbol, args, env, ns):
     return func.call(Expr([func] + args[1].args), env, ns)
 
 FUNCTOOLS.register("apply", Builtin("apply", interpretApply, [Arg("func", TypeEnum.ANY), Arg("list", TypeEnum.LIST)]))
+
+def interpretReduce(symbol, args, env, ns):
+    func = args[0]
+    if not (isinstance(func, Function) or isinstance(func, NebSyntax)):
+        raise InterpretPanic(symbol, "requires a symbol as its first argument", func)
+
+    ret = args[2]  # this is the accumulator
+    for arg in args[1].args:
+        ret = func.call(Expr([func, ret, arg]), env, ns)
+    return ret
+
+FUNCTOOLS.register("reduce", Builtin("reduce", interpretReduce, [Arg("func", TypeEnum.ANY), Arg("list", TypeEnum.LIST), Arg("accum", TypeEnum.ANY)], return_type=Type(":list")))