From fba426b3910f16c8abc6f819da3138f03e5f0b1a Mon Sep 17 00:00:00 2001
From: Charlie Stanton <charlie@shtanton.xyz>
Date: Sun, 19 Feb 2023 08:59:16 +0000
Subject: Introduces subex processing

Doesn't integrate it at all yet
---
 subex/subexast.go | 163 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 163 insertions(+)
 create mode 100644 subex/subexast.go

(limited to 'subex/subexast.go')

diff --git a/subex/subexast.go b/subex/subexast.go
new file mode 100644
index 0000000..c583245
--- /dev/null
+++ b/subex/subexast.go
@@ -0,0 +1,163 @@
+package subex
+
+import (
+	"fmt"
+)
+
+type SubexAST interface {
+	compileWith(next SubexState) SubexState
+}
+
+type SubexASTConcat struct {
+	first, second SubexAST
+}
+func (ast SubexASTConcat) compileWith(next SubexState) SubexState {
+	return ast.first.compileWith(ast.second.compileWith(next))
+}
+func (ast SubexASTConcat) String() string {
+	return fmt.Sprintf("(%v)(%v)", ast.first, ast.second)
+}
+
+type SubexASTStore struct {
+	match SubexAST
+	slot rune
+}
+func (ast SubexASTStore) compileWith(next SubexState) SubexState {
+	return &SubexStoreState {
+		match: ast.match.compileWith(&SubexNoneState{}),
+		slot: ast.slot,
+		next: next,
+	}
+}
+func (ast SubexASTStore) String() string {
+	return fmt.Sprintf("$%c(%v)", ast.slot, ast.match)
+}
+
+type SubexASTOr struct {
+	first, second SubexAST
+}
+func (ast SubexASTOr) compileWith(next SubexState) SubexState {
+	return &SubexGroupState {
+		ast.first.compileWith(next),
+		ast.second.compileWith(next),
+	}
+}
+
+type SubexASTMaximise struct {
+	content SubexAST
+}
+func (ast SubexASTMaximise) compileWith(next SubexState) SubexState {
+	state := &SubexGroupState {
+		nil,
+		next,
+	}
+	state.first = ast.content.compileWith(state)
+	return state
+}
+func (ast SubexASTMaximise) String() string {
+	return fmt.Sprintf("(%v)*", ast.content)
+}
+
+type SubexASTMinimise struct {
+	content SubexAST
+}
+func (ast SubexASTMinimise) compileWith(next SubexState) SubexState {
+	state := &SubexGroupState {
+		next,
+		nil,
+	}
+	state.second = ast.content.compileWith(state)
+	return state
+}
+func (ast SubexASTMinimise) String() string {
+	return fmt.Sprintf("(%v)-", ast.content)
+}
+
+type SubexASTRepeat struct {
+	content SubexAST
+	min, max int
+}
+func (ast SubexASTRepeat) compileWith(next SubexState) SubexState {
+	for i := ast.min; i < ast.max; i += 1 {
+		next = &SubexGroupState {
+			ast.content.compileWith(next),
+			next,
+		}
+	}
+	for i := 0; i < ast.min; i += 1 {
+		next = ast.content.compileWith(next)
+	}
+	return next
+}
+
+type SubexASTCopyRune rune
+func (ast SubexASTCopyRune) compileWith(next SubexState) SubexState {
+	return &SubexCopyRuneState{
+		rune: rune(ast),
+		next: next,
+	}
+}
+
+type SubexASTCopyAny struct {}
+func (ast SubexASTCopyAny) compileWith(next SubexState) SubexState {
+	return &SubexCopyAnyState{next}
+}
+func (ast SubexASTCopyAny) String() string {
+	return "."
+}
+
+type SubexASTOutput struct {
+	replacement []TransducerOutput
+}
+func (ast SubexASTOutput) compileWith(next SubexState) SubexState {
+	return &SubexOutputState{
+		content: ast.replacement,
+		next: next,
+	}
+}
+
+type SubexASTTry struct {
+	content SubexAST
+}
+func (ast SubexASTTry) compileWith(next SubexState) SubexState {
+	return &SubexGroupState {
+		ast.content.compileWith(next),
+		next,
+	}
+}
+
+type SubexASTMaybe struct {
+	content SubexAST
+}
+func (ast SubexASTMaybe) compileWith(next SubexState) SubexState {
+	return &SubexGroupState {
+		next,
+		ast.content.compileWith(next),
+	}
+}
+
+type SubexASTJoin struct {
+	content, delimiter SubexAST
+}
+func (ast SubexASTJoin) compileWith(next SubexState) SubexState {
+	afterContentState := &SubexGroupState {
+		nil,
+		next,
+	}
+	manyContentsState := ast.content.compileWith(afterContentState)
+	afterContentState.first = ast.delimiter.compileWith(manyContentsState)
+	return &SubexGroupState {
+		manyContentsState,
+		next,
+	}
+}
+
+type SubexASTRange struct {
+	parts map[rune]rune
+}
+func (ast SubexASTRange) compileWith(next SubexState) SubexState {
+	return &SubexRangeState {
+		parts: ast.parts,
+		next: next,
+	}
+}
-- 
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