From e72f1d833751756fdb237a35ff0a9549487bf0bf Mon Sep 17 00:00:00 2001
From: Alex Gilding <alexg.nvfp@gmail.com>
Date: Tue, 28 Apr 2015 20:24:13 +0100
Subject: [PATCH] Add indentation for Scheme

Just copied over the Clojure indentation rules to Scheme and changed
the keywords to suit the language, so that Scheme programs can be
automatically indented too
---
 lib/ace/mode/scheme.js | 77 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/lib/ace/mode/scheme.js b/lib/ace/mode/scheme.js
index aa462a10..2360b3da 100644
--- a/lib/ace/mode/scheme.js
+++ b/lib/ace/mode/scheme.js
@@ -39,15 +39,92 @@ define(function(require, exports, module) {
 var oop = require("../lib/oop");
 var TextMode = require("./text").Mode;
 var SchemeHighlightRules = require("./scheme_highlight_rules").SchemeHighlightRules;
+var MatchingParensOutdent = require("./matching_parens_outdent").MatchingParensOutdent;
 
 var Mode = function() {
     this.HighlightRules = SchemeHighlightRules;
+	this.$outdent = new MatchingParensOutdent();
 };
 oop.inherits(Mode, TextMode);
 
 (function() {
        
     this.lineCommentStart = ";";
+    this.minorIndentFunctions = ["define", "lambda", "define-macro", "define-syntax", "syntax-rules", "define-record-type", "define-structure"];
+
+    this.$toIndent = function(str) {
+        return str.split('').map(function(ch) {
+            if (/\s/.exec(ch)) {
+                return ch;
+            } else {
+                return ' ';
+            }
+        }).join('');
+    };
+
+    this.$calculateIndent = function(line, tab) {
+        var baseIndent = this.$getIndent(line);
+        var delta = 0;
+        var isParen, ch;
+        // Walk back from end of line, find matching braces
+        for (var i = line.length - 1; i >= 0; i--) {
+            ch = line[i];
+            if (ch === '(') {
+                delta--;
+                isParen = true;
+            } else if (ch === '(' || ch === '[' || ch === '{') {
+                delta--;
+                isParen = false;
+            } else if (ch === ')' || ch === ']' || ch === '}') {
+                delta++;
+            }
+            if (delta < 0) {
+                break;
+            }
+        }
+        if (delta < 0 && isParen) {
+            // Were more brackets opened than closed and was a ( left open?
+            i += 1;
+            var iBefore = i;
+            var fn = '';
+            while (true) {
+                ch = line[i];
+                if (ch === ' ' || ch === '\t') {
+                    if(this.minorIndentFunctions.indexOf(fn) !== -1) {
+                        return this.$toIndent(line.substring(0, iBefore - 1) + tab);
+                    } else {
+                        return this.$toIndent(line.substring(0, i + 1));
+                    }
+                } else if (ch === undefined) {
+                    return this.$toIndent(line.substring(0, iBefore - 1) + tab);
+                }
+                fn += line[i];
+                i++;
+            }
+        } else if(delta < 0 && !isParen) {
+            // Were more brackets openend than closed and was it not a (?
+            return this.$toIndent(line.substring(0, i+1));
+        } else if(delta > 0) {
+            // Mere more brackets closed than opened? Outdent.
+            baseIndent = baseIndent.substring(0, baseIndent.length - tab.length);
+            return baseIndent;
+        } else {
+            // Were they nicely matched? Just indent like line before.
+            return baseIndent;
+        }
+    };
+
+    this.getNextLineIndent = function(state, line, tab) {
+        return this.$calculateIndent(line, tab);
+    };
+
+    this.checkOutdent = function(state, line, input) {
+        return this.$outdent.checkOutdent(line, input);
+    };
+
+    this.autoOutdent = function(state, doc, row) {
+        this.$outdent.autoOutdent(doc, row);
+    };
     
     this.$id = "ace/mode/scheme";
 }).call(Mode.prototype);