From ad7833134883b6cd2c155ee8be3ff8d324c72ef3 Mon Sep 17 00:00:00 2001
From: Brian Evans <bevans@formulafolios.com>
Date: Fri, 7 Feb 2020 16:27:02 -0800
Subject: [PATCH] Adds optional paren matching to keyboard input

---
 config.h |  3 +++
 hermes.c | 23 +++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/config.h b/config.h
index d00e659..2bbe5b6 100644
--- a/config.h
+++ b/config.h
@@ -9,6 +9,9 @@
 // Set global tab width for the editor here
 static const int tabwidth = 4;
 
+// Turn on or off paren matching for: (, {, [
+static const int MATCH_PARENS = 1;
+
 /* 
  * Values from 1 to 256 representing 256 color/8-bit pallate
  * see: https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
diff --git a/hermes.c b/hermes.c
index 1d527a6..a436aa5 100644
--- a/hermes.c
+++ b/hermes.c
@@ -353,6 +353,19 @@ void editorUpdateSyntax(erow *row) {
     editorUpdateSyntax(&E.row[row->idx + 1]);
 }
 
+char editorGetMatchingParen(char c) {
+  switch (c) {
+    case '{':
+      return '}';
+    case '(':    
+      return ')';
+    case '[':
+      return ']';
+    default:
+      return ' ';
+  }
+}
+
 int editorSyntaxToColor(int hl) {
   switch (hl) {
     case HL_NUMBER:    return HL_NUMBER_COLOR;
@@ -1152,6 +1165,16 @@ void editorInputKp(int c) {
       if (c == DEL_KEY) editorMoveCursor(ARROW_RIGHT);
       editorDeleteChar();
       break;
+    case '(':
+    case '{':
+    case '[':
+      editorInsertChar(c);
+      if (MATCH_PARENS) {
+        char match = editorGetMatchingParen(c);
+        editorInsertChar(match);
+        editorMoveCursor(ARROW_LEFT);
+      }
+      break;
     default:
       editorInsertChar(c);
       break;