From 9ac6086bad61aae32cd5353b5f4ad3af5dc1ee3e Mon Sep 17 00:00:00 2001
From: Dave Holoway <adelphes@gmail.com>
Date: Tue, 16 Jun 2020 15:42:48 +0100
Subject: [PATCH] add support for parsing parameterless lambdas

---
 langserver/java/body-parser3.js | 25 +++++++++++++++++++++++++
 langserver/java/tokenizer.js    |  6 ++++--
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/langserver/java/body-parser3.js b/langserver/java/body-parser3.js
index f144942..58f1885 100644
--- a/langserver/java/body-parser3.js
+++ b/langserver/java/body-parser3.js
@@ -522,6 +522,18 @@ class BracketedExpression extends Expression {
         this.expression = expression;
     }
 }
+class LambdaExpression extends Expression {
+    /**
+     * 
+     * @param {*[]} params 
+     * @param {Expression|Block} body 
+     */
+    constructor(params, body) {
+        super();
+        this.params = params;
+        this.body = body;
+    }
+}
 class IncDecExpression extends Expression {
     /**
      * @param {ResolvedIdent} expr 
@@ -1674,6 +1686,19 @@ function rootTerm(tokens, mdecls, scope, imports, typemap) {
             return newTerm(tokens, mdecls, scope, imports, typemap);
         case 'open-bracket':
             tokens.inc();
+            if (tokens.isValue(')')) {
+                // parameterless lambda
+                tokens.expectValue('->');
+                let ident, lambdaBody = null;
+                if (tokens.current.value === '{') {
+                    // todo - parse lambda body
+                    skipBody(tokens);
+                } else {
+                    lambdaBody = expression(tokens, mdecls, scope, imports, typemap);
+                    ident = `() -> ${lambdaBody.source}`;
+                }
+                return new ResolvedIdent(ident, [new LambdaExpression([], lambdaBody)]);
+            }
             matches = expression(tokens, mdecls, scope, imports, typemap);
             tokens.expectValue(')');
             if (isCastExpression(tokens.current, matches)) {
diff --git a/langserver/java/tokenizer.js b/langserver/java/tokenizer.js
index e43a405..3e65ee4 100644
--- a/langserver/java/tokenizer.js
+++ b/langserver/java/tokenizer.js
@@ -90,7 +90,7 @@ class Token extends TextBlock {
  */
 function tokenize(source, offset = 0, length = source.length) {
     const text = source.slice(offset, offset + length);
-    const raw_token_re = /(\s+|\/\/.*|\/\*[\d\D]*?\*\/|\/\*[\d\D]*)|("[^\r\n\\"]*(?:\\.[^\r\n\\"]*)*"|".*)|('\\u[\da-fA-F]{0,4}'?|'\\?.?'?)|(\.?\d)|([\p{L}\p{N}$_]+)|(\()|([;,?:(){}\[\]@]|\.(?:\.\.)?)|([!=/%*^]=?|<<?=?|>>?>?=?|&[&=]?|\|[|=]?|(\+\+|--)|[+-]=?|~)|$/gu;
+    const raw_token_re = /(\s+|\/\/.*|\/\*[\d\D]*?\*\/|\/\*[\d\D]*)|("[^\r\n\\"]*(?:\\.[^\r\n\\"]*)*"|".*)|('\\u[\da-fA-F]{0,4}'?|'\\?.?'?)|(\.?\d)|([\p{L}\p{N}$_]+)|(\()|([;,?:(){}\[\]@]|\.(?:\.\.)?)|([!=/%*^]=?|<<?=?|>>?>?=?|&[&=]?|\|[|=]?|(\+\+|--)|->|[+-]=?|~)|$/gu;
     const raw_token_types = [
         'wsc',
         'string-literal',
@@ -209,7 +209,7 @@ function tokenize(source, offset = 0, length = source.length) {
  * [~!]   unary
  * ```
  */
-const operator_re = /^(?:(=|[/%*&|^+-]=|>>>?=|<<=)|(\+\+|--)|([!=]=)|([<>]=?)|([&|^])|(<<|>>>?)|(&&|[|][|])|([*%/])|([+-])|([~!]))$/;
+const operator_re = /^(?:(=|[/%*&|^+-]=|>>>?=|<<=)|(\+\+|--)|([!=]=)|([<>]=?)|([&|^])|(<<|>>>?)|(&&|[|][|])|([*%/])|(->)|([+-])|([~!]))$/;
 /**
  * @typedef {
     'assignment-operator'|
@@ -220,6 +220,7 @@ const operator_re = /^(?:(=|[/%*&|^+-]=|>>>?=|<<=)|(\+\+|--)|([!=]=)|([<>]=?)|([
     'shift-operator'|
     'logical-operator'|
     'muldiv-operator'|
+    'lambda-operator'|
     'plumin-operator'|
     'unary-operator'} OperatorKind
  */
@@ -233,6 +234,7 @@ const operator_token_types = [
     'shift-operator',
     'logical-operator',
     'muldiv-operator',
+    'lambda-operator',
     'plumin-operator',
     'unary-operator',
 ]