implement pipe

2 files changed, 15 insertions, 0 deletions

diff --git a/interpreter.py b/interpreter.py
index 6a88c57..ee7069c 100644
--- a/interpreter.py
+++ b/interpreter.py
@@ -278,6 +278,19 @@ def interpretForCount(expr, env):
 
 GLOBALS.register("for-count", Builtin(interpretForCount))
 
+def interpretPipe(expr, env):
+    if len(expr.args) < 2:
+        raise Exception("'|' takes at least two expressions")
+    new_env = Environment(env)
+    pipe = None
+    for arg in expr.args:
+        if pipe is not None:
+            new_env.register("items", pipe)
+        pipe = Expr.Literal(evaluate(arg, new_env))
+    return pipe
+
+GLOBALS.register("|", Builtin(interpretPipe))
+
 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 e98972f..aa2d107 100644
--- a/lexer.py
+++ b/lexer.py
@@ -46,6 +46,7 @@ class TokenType(Enum):
     # flow
     IF = auto()
     FOR_COUNT = auto()
+    PIPE = auto()
 
     # keywords
     DEF = auto()
@@ -70,6 +71,7 @@ keywords = {
     "or": TokenType.OR,
     "if": TokenType.IF,
     "for-count": TokenType.FOR_COUNT,
+    "|": TokenType.PIPE,
     "def": TokenType.DEF,
     "lambda": TokenType.LAMBDA }