From 8dcebe3930809c0c1404fa37fceb5f48e5e0a6ee Mon Sep 17 00:00:00 2001
From: Jaime Humberto Macias Bustamante <jamextreme140@outlook.com>
Date: Wed, 3 Sep 2025 20:13:39 -0700
Subject: [PATCH] Regular Expression support (regex)

---
 hscript/Bytes.hx   |  2 ++
 hscript/Expr.hx    |  1 +
 hscript/Interp.hx  |  2 ++
 hscript/Parser.hx  | 55 +++++++++++++++++++++++++++++++++++++++++++---
 hscript/Printer.hx |  3 +++
 5 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/hscript/Bytes.hx b/hscript/Bytes.hx
index 20619bf..b423d0e 100644
--- a/hscript/Bytes.hx
+++ b/hscript/Bytes.hx
@@ -134,6 +134,8 @@ class Bytes {
 			// TODO
 		case ECast(e, _):
 			// TODO
+		case ERegex(e, f):
+			// TODO
 		case EConst(c):
 			doEncodeConst(c);
 		case EIdent(v):
diff --git a/hscript/Expr.hx b/hscript/Expr.hx
index f313d19..3733594 100644
--- a/hscript/Expr.hx
+++ b/hscript/Expr.hx
@@ -84,6 +84,7 @@ enum Expr {
 	EClass( name:String, fields:Array<Expr>, ?extend:String, interfaces:Array<String>, ?isFinal:Bool, ?isPrivate:Bool );
 	EEnum( en:EnumDecl, ?isAbstract:Bool );
 	ECast(e:Expr, ?t:CType);
+	ERegex(e:String, flags:String);
 }
 
 @:structInit
diff --git a/hscript/Interp.hx b/hscript/Interp.hx
index b548f83..6b4ca96 100644
--- a/hscript/Interp.hx
+++ b/hscript/Interp.hx
@@ -885,6 +885,8 @@ class Interp {
 				variables.set(en.name, enumThingy);
 			case ECast(e, _): // TODO
 				return expr(e);
+			case ERegex(e, f):
+				return new EReg(e, f);
 			case EConst(c):
 				switch (c) {
 					case CInt(v): return v;
diff --git a/hscript/Parser.hx b/hscript/Parser.hx
index ff75805..38ab0c1 100644
--- a/hscript/Parser.hx
+++ b/hscript/Parser.hx
@@ -43,6 +43,7 @@ enum Token {
 	TDoubleDot;
 	TMeta( s : String );
 	TPrepro( s : String );
+	TRegex( e : String, f:String );
 }
 
 @:structInit
@@ -72,6 +73,11 @@ class Parser {
 	**/
 	public var allowJSON : Bool;
 
+	/**
+		activate Regular Expression parsing 
+	**/
+	public var allowRegex : Bool;
+
 	/**
 		allow types declarations
 	**/
@@ -115,6 +121,8 @@ class Parser {
 
 	#end
 
+	static inline var regexFlags: String = "igmsu";
+
 	public function new() {
 		line = 1;
 		opChars = "+*/-=!><&|^%~";
@@ -513,6 +521,8 @@ class Parser {
 			var e = parseExpr();
 			isVar = false;
 			return mk(EMeta(id, args, e),p1);
+		case TRegex(e, f) if(allowRegex):
+			return mk(ERegex(e, f), p1);
 		default:
 			return unexpected(tk);
 		}
@@ -1863,7 +1873,7 @@ class Parser {
 		return StringTools.fastCodeAt(input, readPos++);
 	}
 
-	function readString( until:Int ):String {
+	function readString( until:Int, regex:Bool = false ):String {
 		var c = 0;
 		var b = new StringBuf();
 		var esc = false;
@@ -1911,7 +1921,7 @@ class Parser {
 					b.addChar(k);
 				default: invalidChar(c);
 				}
-			} else if( c == 92 )
+			} else if( c == 92 && !regex)
 				esc = true;
 			else if( c == until )
 				break;
@@ -1923,6 +1933,39 @@ class Parser {
 		return b.toString();
 	}
 
+	function readFlags():String {
+		if(!allowRegex) return null;
+		var c = 0;
+		var b = new StringBuf();
+		var old = line;
+		var s = input;
+		#if hscriptPos
+		var p1 = readPos - 1;
+		#end
+
+		while(true) {
+			var c = readChar();
+			if( StringTools.isEof(c) ) {
+				line = old;
+				error(EUnterminatedString, p1, p1);
+				break;
+			}
+			// semicolon
+			if(c == 59) {
+				this.char = c;
+				break;
+			}
+			
+			var f = String.fromCharCode(c);
+			if(regexFlags.indexOf(f) != -1) 
+				b.addChar(c);
+			else
+				invalidChar(c);
+		}
+
+		return b.toString();
+	}
+
 	function token():Token {
 	//function token(?infos : Null<haxe.PosInfos>) {
 		//function ttrace(v:Dynamic, ?infos : Null<haxe.PosInfos>) {
@@ -2146,7 +2189,7 @@ class Parser {
 				invalidChar(char);
 			default:
 				if( ops[char] ) {
-					var op = String.fromCharCode(char);
+					var op:String = String.fromCharCode(char);
 					while( true ) {
 						char = readChar();
 						if( StringTools.isEof(char) ) char = 0;
@@ -2156,6 +2199,11 @@ class Parser {
 						}
 						var pop = op;
 						op += String.fromCharCode(char);
+						if( allowRegex && op == "~/") {
+							var e = readString(char, true);
+							var f = readFlags();
+							return TRegex(e, f);
+						}
 						if( !opPriority.exists(op) && opPriority.exists(pop) ) {
 							if( op == "//" || op == "/*" )
 								return tokenComment(op,char);
@@ -2370,6 +2418,7 @@ class Parser {
 		case TDoubleDot: ":";
 		case TMeta(id): "@" + id;
 		case TPrepro(id): "#" + id;
+		case TRegex(e, f): '~/$e/${f == null ? '' : f}';
 		}
 	}
 
diff --git a/hscript/Printer.hx b/hscript/Printer.hx
index b671779..34fb765 100644
--- a/hscript/Printer.hx
+++ b/hscript/Printer.hx
@@ -186,6 +186,9 @@ class Printer {
 				addType(t);
 				add(")");
 			}
+		case ERegex(e, f):
+			add('~/$e/$f');
+			add(';\n');
 		case EConst(c):
 			switch( c ) {
 			case CInt(i): add(i);