lambdas!

1 files changed, 46 insertions, 0 deletions

diff --git a/parser.d b/parser.d
index 68f5093..e51b5e1 100644
--- a/parser.d
+++ b/parser.d
@@ -12,6 +12,7 @@ enum FormType {
     NIL,
     SYMBOL,
     FUNC,
+    LAMBDA,
     DEF,
     BLOCK,
     IF,
@@ -211,6 +212,21 @@ class Func : Form {
     }
 }
 
+class Lambda : Form {
+
+    Cons args;
+    Form[] lambdaBody;
+
+    this (int line) {
+        this.line = line;
+        this.type = FormType.LAMBDA;
+    }
+
+    void addToBody(Form f) {
+        this.lambdaBody ~= f;
+    }
+}
+
 class Def : Form {
 
     Symbol name;
@@ -449,6 +465,34 @@ class Parser {
         return def;
     }
 
+    Form parseLambda() {
+        // we've parsed `lambda` already
+        Form args = parseForm();
+        if (args.type != FormType.CONS && args.type != FormType.NIL) {
+            return new ParseError("func definitions expect a list of arguments", line);
+        }
+
+        Lambda lamb = new Lambda(line);
+        lamb.args = cast(Cons)args;
+
+        char next;
+        while(peekable()) {
+            next = peek();
+            if (next == ')') {
+                break;
+            }
+            lamb.addToBody(this.parseForm());
+        }
+
+        if (!peekable()) {
+            return new ParseError("unterminated lambda", line);
+        }
+
+        advance();  // consume closing paren
+
+        return lamb;
+    }
+
     Form parseFunc() {
         // we've parsed `func`, but not the symbol yet
         Form sym = parseForm();
@@ -579,6 +623,8 @@ class Parser {
             switch (s.name) {
                 case "func":
                     return parseFunc();
+                case "lambda":
+                    return parseLambda();
                 case "def":
                     return parseDef();
                 case "block":