move Arg and Environment to structs

1 files changed, 53 insertions, 0 deletions

diff --git a/neb/structs.py b/neb/structs.py
index 09807db..3aac72a 100644
--- a/neb/structs.py
+++ b/neb/structs.py
@@ -106,3 +106,56 @@ class List:
     def __str__(self):
         return "(" +  " ".join(f"{arg}" for arg in self.args) + ")"
 
+# function things
+class Arg:
+
+    def __init__(self, name, type_, *, optional=False, lazy=False):
+        self.name = name
+        self.type_ = type_
+        self.optional = optional
+        self.lazy = lazy
+
+    def __str__(self):
+        opt = "?" if self.optional else ""
+        lazy = "~" if self.lazy else ""
+        return f"{lazy}{opt}{self.name} {self.type_}"
+
+class Environment:
+
+    def __init__(self, parent=None):
+        self.parent = parent
+        self.environment = {}
+
+    def register(self, key, value):
+        self.environment[key] = value
+
+    def reregister(self, key, value):
+        if not self.contains(key):
+            raise NebPanic(f"undefined symbol: '{key}")
+        if key in self.environment:
+            self.register(key, value)
+        else:
+            self.parent.reregister(key, value)
+
+    def contains(self, key):
+        if key in self.environment:
+            return True
+        elif self.parent is not None:
+            return self.parent.contains(key)
+        else:
+            return False
+
+    def get(self, key):
+        if not self.contains(key):
+            raise NebPanic(f"undefined symbol: '{key}")
+        if key in self.environment:
+            return self.environment[key]
+        else:
+            return self.parent.get(key)
+
+    def __str__(self):
+        out = ""
+        for k, v in self.environment.items():
+            out += f"{k}: {v}, "
+        return out
+