From 8ac12c99fc59b01da40c2939cb4a7b72d32d2153 Mon Sep 17 00:00:00 2001
From: Charlie Stanton <charlie@shtanton.xyz>
Date: Sat, 27 Apr 2024 09:29:46 +0100
Subject: Add iterating destructures

---
 subex/parse.go | 61 +++++++++++++++++++++++++++++-----------------------------
 1 file changed, 30 insertions(+), 31 deletions(-)

(limited to 'subex/parse.go')

diff --git a/subex/parse.go b/subex/parse.go
index b6bf2f6..9a7a75c 100644
--- a/subex/parse.go
+++ b/subex/parse.go
@@ -55,6 +55,12 @@ func (s Structure) String() string {
 	}
 }
 
+type DestructureMethod int
+const (
+	Normal DestructureMethod = iota
+	Iterate
+)
+
 type RuneReader interface {
 	Next() rune
 	Rewind()
@@ -361,8 +367,14 @@ func parseRuneReplacement(l RuneReader, end rune) (output SubexAST) {
 // }
 
 func parseDestructure(l RuneReader, destructure Structure, inType Type) (lhs SubexAST, outType Type) {
-	if !accept(l, "(") {
-		panic("Missing ( after destructure start")
+	var method rune
+	switch l.Next() {
+	case '(':
+		method = ')'
+	case '[':
+		method = ']'
+	default:
+		panic("Missing ( or [ after destructure start")
 	}
 
 	var innerInType Type
@@ -390,8 +402,22 @@ func parseDestructure(l RuneReader, destructure Structure, inType Type) (lhs Sub
 	resolveTypes(inType, expectedInType)
 
 	lhs, innerOutType := parseSubex(l, 0, innerInType)
-	if !accept(l, ")") {
-		panic("Missing matching )")
+	if !accept(l, string(method)) {
+		panic("Missing matching ) or ]")
+	}
+
+	switch method {
+	case ')':
+	case ']':
+		lhs = SubexASTRepeat {
+			Content: lhs,
+			Acceptable: []ConvexRange{{
+				Start: -1,
+				End: 0,
+			}},
+		}
+	default:
+		panic("Invalid method")
 	}
 
 	var structure Structure
@@ -487,20 +513,6 @@ func parseSubex(l RuneReader, minPower int, inType Type) (lhs SubexAST, outType
 		case ')', ']', '|', ';', '{', '+', '*', '/', '!', '=', '$':
 			l.Rewind()
 			return SubexASTEmpty{}, inType
-		// case '=':
-		// 	replacement := parseReplacement(l)
-		// 	lhs = SubexASTOutput{replacement}
-		// case '^':
-		// 	replacement := parseReplacement(l)
-		// 	replacement = append(
-		// 		[]OutputContentAST{OutputValueLiteralAST {walk.NewAtomStringTerminal()}},
-		// 		replacement...
-		// 	)
-		// 	replacement = append(
-		// 		replacement,
-		// 		OutputValueLiteralAST {walk.NewAtomStringTerminal()},
-		// 	)
-		// 	lhs = SubexASTOutput {replacement}
 		case '.':
 			outType = inType
 			if inType == RuneType {
@@ -569,14 +581,10 @@ func parseSubex(l RuneReader, minPower int, inType Type) (lhs SubexAST, outType
 				lhs = SubexASTProduct {lhs}
 				resolveTypes(inType, ValueType)
 				outType = resolveTypes(outType, ValueType)
-			// case r == '/' && minPower <= 4:
-				// lhs = SubexASTReciprocal {lhs}
 			case r == '!' && minPower <= 4:
 				lhs = SubexASTNot {lhs}
 				resolveTypes(inType, ValueType)
 				outType = resolveTypes(outType, ValueType)
-			// case r == '=' && minPower <= 4:
-				// lhs = SubexASTEqual {lhs}
 			case r == '$' && minPower <= 4:
 				slot := l.Next()
 				if slot == eof {
@@ -608,15 +616,6 @@ func parseSubex(l RuneReader, minPower int, inType Type) (lhs SubexAST, outType
 					panic("Missing subex after |")
 				}
 				lhs = SubexASTOr{lhs, rhs}
-			/*case r == ';' && minPower <= 10:
-				rhs := parseSubex(l, 11, inType, outType)
-				if rhs == nil {
-					panic("Missing subex after ;")
-				}
-				lhs = SubexASTJoin {
-					Content: lhs,
-					Delimiter: rhs,
-				}*/
 			default:
 				l.Rewind()
 				break loop
-- 
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