From 90ff40928113a8a8036e6685f76c8ec821a4f4f3 Mon Sep 17 00:00:00 2001
From: Robin Jadoul <robin.jadoul@gmail.com>
Date: Mon, 25 Apr 2016 10:43:06 +0200
Subject: [PATCH] Regex parsing: add escape characters

---
 src/re.cpp | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 50 insertions(+), 1 deletion(-)

diff --git a/src/re.cpp b/src/re.cpp
index 63e4e40..a51b875 100644
--- a/src/re.cpp
+++ b/src/re.cpp
@@ -119,6 +119,44 @@ namespace lxs {
             stk.push(tp);
         }
 
+        std::shared_ptr<RE> parseEscapeChar(char c) {
+            switch (c)
+            {
+                case '\\':
+                case '*':
+                case '+':
+                case '|':
+                case '(':
+                case ')':
+                case '[':
+                case ']':
+                case '?':
+                case '.':
+                case '\'':
+                case '"':
+                    break;
+                case 'n':
+                    c = '\n'; break;
+                case 'r':
+                    c = '\r'; break;
+                case 'b':
+                    c = '\b'; break;
+                case 't':
+                    c = '\t'; break;
+                case 's':
+                    c = ' '; break;
+                case 'a':
+                    c = '\a'; break;
+                case 'f':
+                    c = '\f'; break;
+                case 'v':
+                    c = '\v'; break;
+                default:
+                    throw SyntaxError(("Invalid escape sequence: \\" + std::string(1, c)).c_str());
+            }
+            return std::make_shared<SingleRE>(c);
+        }
+
         std::shared_ptr<RE> parseRE(string& input, size_t& idx)
         {
             stack<std::shared_ptr<RE> > stk;
@@ -131,9 +169,20 @@ namespace lxs {
                         idx++;
                         if (idx >= input.length())
                             throw SyntaxError("Escape sequence at the end of the string");
-                        //TODO: escape chars
                         else
                             throw SyntaxError(("invalid escape sequence: \\" + string(1, input[idx])).c_str());
+                        stk.push(parseEscapeChar(input[idx++]));
+                        break;
+
+                    case '[':
+                        //TODO: parse character classes
+                        break;
+
+                    case '.':
+                        //TODO: any character
+
+                    case ']':
+                        throw SyntaxError("Unopened ']'");
                         break;
 
                     case '*':