From 3636825c64bb6c172b0858d7a08c30acfcd68bdd Mon Sep 17 00:00:00 2001
From: Charlie Stanton <charlie@shtanton.xyz>
Date: Wed, 21 Sep 2022 20:44:56 +0100
Subject: Adds the or operator |

---
 main/main.go | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

(limited to 'main/main.go')

diff --git a/main/main.go b/main/main.go
index 7bb5152..08514ab 100644
--- a/main/main.go
+++ b/main/main.go
@@ -95,7 +95,7 @@ func parseRegex(l *RuneReader, minPower int) RegexAST {
 	switch r {
 		case eof:
 			return nil
-		case ')', '*', '-':
+		case ')', '*', '-', '|':
 			l.rewind()
 			return nil
 		case '(':
@@ -122,6 +122,12 @@ func parseRegex(l *RuneReader, minPower int) RegexAST {
 				lhs = RegexASTMaximise{lhs}
 			case r == '-' && minPower <= 4:
 				lhs = RegexASTMinimise{lhs}
+			case r == '|' && minPower <= 2:
+				rhs := parseRegex(l, 3)
+				if rhs == nil {
+					panic("Missing regex after |")
+				}
+				lhs = RegexASTOr{lhs, rhs}
 			default:
 				l.rewind()
 				break loop
@@ -141,7 +147,7 @@ func parseSubex(l *RuneReader, minPower int) TransducerAST {
 			if !l.accept(")") {
 				panic("Missing matching )")
 			}
-		case ')', '*', '-':
+		case ')', '*', '-', '|':
 			l.rewind()
 			return nil
 		case '$':
@@ -179,6 +185,12 @@ func parseSubex(l *RuneReader, minPower int) TransducerAST {
 				lhs = TransducerASTMaximise{lhs}
 			case r == '-' && minPower <= 4:
 				lhs = TransducerASTMinimise{lhs}
+			case r == '|' && minPower <= 2:
+				rhs := parseSubex(l, 3)
+				if rhs == nil {
+					panic("Missing subex after |")
+				}
+				lhs = TransducerASTOr{lhs, rhs}
 			default:
 				l.rewind()
 				break loop
@@ -290,6 +302,16 @@ func (ast RegexASTConcat) String() string {
 	return fmt.Sprintf("Concat{%v, %v}", ast.first, ast.second)
 }
 
+type RegexASTOr struct {
+	first, second RegexAST
+}
+func (ast RegexASTOr) compileWith(next RegexState) RegexState {
+	return RegexGroupState{
+		ast.first.compileWith(next),
+		ast.second.compileWith(next),
+	}
+}
+
 type RegexASTMaximise struct {
 	content RegexAST
 }
@@ -470,6 +492,16 @@ func (ast TransducerASTStore) String() string {
 	return fmt.Sprintf("$%c(%v)", ast.slot, ast.match)
 }
 
+type TransducerASTOr struct {
+	first, second TransducerAST
+}
+func (ast TransducerASTOr) compileWithNext(next TransducerState) TransducerState {
+	return TransducerGroupState {
+		ast.first.compileWithNext(next),
+		ast.second.compileWithNext(next),
+	}
+}
+
 type TransducerASTMaximise struct {
 	content TransducerAST
 }
-- 
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