From 38dc63a67879a42f208b5642a8590e1192e8e2e5 Mon Sep 17 00:00:00 2001
From: Ben Winston
Date: Sat, 20 May 2023 18:58:51 -0400
Subject: global variables

---
 parser.d | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

(limited to 'parser.d')

diff --git a/parser.d b/parser.d
index 20231c9..ef1d736 100644
--- a/parser.d
+++ b/parser.d
@@ -12,6 +12,7 @@ enum FormType {
     NIL,
     SYMBOL,
     FUNC,
+    DEF,
 
     EOF,
     PARSE_ERROR
@@ -134,6 +135,19 @@ class Func : Form {
     }
 }
 
+class Def : Form {
+
+    Symbol name;
+    Form val;
+
+    this(Symbol name, Form val, int line) {
+        this.name = name;
+        this.val = val;
+        this.line = line;
+        this.type = FormType.DEF;
+    }
+}
+
 class Atom : Form {
     Value value;
 
@@ -310,6 +324,23 @@ class Parser {
         return new Atom(to!double(to!string(acc)), line);
     }
 
+    Form parseDef() {
+        // we've parsed `def`, but not the symbol yet
+        Form sym = parseForm();
+        if (sym.type != FormType.SYMBOL) {
+            return new ParseError("func definitions expect a symbol name", line);
+        }
+
+        // get the value
+        Form val = parseForm();
+
+        Def def = new Def(cast(Symbol)sym, val, line);
+
+        advance();  // closing paren
+
+        return def;
+    }
+
     Form parseFunc() {
         // we've parsed `func`, but not the symbol yet
         Form sym = parseForm();
@@ -362,6 +393,8 @@ class Parser {
             switch (s.name) {
                 case "func":
                     return parseFunc();
+                case "def":
+                    return parseDef();
                 default:
                     break;
             }
-- 
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