From f1e5bc37723a4faa30bbfeed392c31489914eb50 Mon Sep 17 00:00:00 2001
From: Charlie Stanton <charlie@shtanton.xyz>
Date: Fri, 21 Apr 2023 09:53:04 +0100
Subject: Add subex syntax to copy across booleans, numbers, strings and values

---
 subex/parse.go      | 12 ++++++++-
 subex/subexast.go   | 49 ++++++++++++++++++++++++++++++++++
 subex/subexstate.go | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 137 insertions(+), 1 deletion(-)

diff --git a/subex/parse.go b/subex/parse.go
index 5675ae0..106663d 100644
--- a/subex/parse.go
+++ b/subex/parse.go
@@ -281,7 +281,7 @@ func parseSubex(l RuneReader, minPower int) SubexAST {
 		case '[':
 			rangeParts := parseRangeSubex(l)
 			lhs = SubexASTRange {rangeParts}
-		case ')', '|', ';', '{', '+', '-', '*', '/', '$':
+		case ')', '|', ';', '{', '+', '-', '*', '/', '!', '$':
 			l.Rewind()
 			return nil
 		case '=':
@@ -289,6 +289,16 @@ func parseSubex(l RuneReader, minPower int) SubexAST {
 			lhs = SubexASTOutput{replacement}
 		case '.':
 			lhs = SubexASTCopyAny{}
+		case '?':
+			lhs = SubexASTCopyBool{}
+		case '%':
+			lhs = SubexASTCopyNumber{}
+		case '_':
+			lhs = SubexASTCopyStringAtom{}
+		case '#':
+			lhs = SubexASTCopyString{}
+		case ',':
+			lhs = SubexASTCopyValue{}
 		case '"':
 			lhs = SubexASTCopyAtom {walk.StringTerminal{}}
 		case '`':
diff --git a/subex/subexast.go b/subex/subexast.go
index 87686b1..baf7a3b 100644
--- a/subex/subexast.go
+++ b/subex/subexast.go
@@ -134,6 +134,55 @@ func (ast SubexASTCopyAtom) compileWith(next SubexState) SubexState {
 	}
 }
 
+// Read in a single atom that must be a boolean and output it unchanged
+type SubexASTCopyBool struct {}
+func (ast SubexASTCopyBool) compileWith(next SubexState) SubexState {
+	return &SubexCopyBoolState {next}
+}
+
+// Read in a single atom that must be a number and output it unchanged
+type SubexASTCopyNumber struct {}
+func (ast SubexASTCopyNumber) compileWith(next SubexState) SubexState {
+	return &SubexCopyNumberState {next}
+}
+
+// Read in a single atom that must be a string atom and output it unchanged
+type SubexASTCopyStringAtom struct {}
+func (ast SubexASTCopyStringAtom) compileWith(next SubexState) SubexState {
+	return &SubexCopyStringAtomState {next}
+}
+
+// Read in a full string value and copy it out unchanged
+// # is equivalent to "_{-0}"
+type SubexASTCopyString struct {}
+func (ast SubexASTCopyString) compileWith(next SubexState) SubexState {
+	stringAtomState := &SubexCopyStringAtomState {
+		next: nil,
+	}
+	stringContentState := &SubexGroupState {
+		&SubexCopyAtomState {
+			atom: walk.StringTerminal{},
+			next: next,
+		},
+		stringAtomState,
+	}
+	stringAtomState.next = stringContentState
+	return &SubexCopyAtomState {
+		atom: walk.StringTerminal{},
+		next: stringContentState,
+	}
+}
+
+// Read in a value and copy it out unchanged
+// , is equivalent to `null`|?|%|#|[`{}[]`]
+type SubexASTCopyValue struct {}
+func (ast SubexASTCopyValue) compileWith(next SubexState) SubexState {
+	return &SubexGroupState {
+		SubexASTCopyString{}.compileWith(next),
+		&SubexCopyNonStringAtomState {next},
+	}
+}
+
 // Read in any single Atom and output it unchanged
 type SubexASTCopyAny struct {}
 func (ast SubexASTCopyAny) compileWith(next SubexState) SubexState {
diff --git a/subex/subexstate.go b/subex/subexstate.go
index cca7a88..997e6ce 100644
--- a/subex/subexstate.go
+++ b/subex/subexstate.go
@@ -135,6 +135,83 @@ func (state SubexCopyAtomState) accepting(store Store, outputStack OutputStack)
 	return nil
 }
 
+// Read in a boolean atom and output it
+type SubexCopyBoolState struct {
+	next SubexState
+}
+func (state SubexCopyBoolState) eat(store Store, outputStack OutputStack, char walk.Atom) []SubexBranch {
+	_, isBool := char.(walk.ValueBool)
+	if isBool {
+		return []SubexBranch{{
+			state: state.next,
+			outputStack: topAppend(outputStack, []walk.Atom{char}),
+			store: store,
+		}}
+	}
+	return nil
+}
+func (state SubexCopyBoolState) accepting(store Store, outputStack OutputStack) []OutputStack {
+	return nil
+}
+
+// Read in a number atom and output it
+type SubexCopyNumberState struct {
+	next SubexState
+}
+func (state SubexCopyNumberState) eat(store Store, outputStack OutputStack, char walk.Atom) []SubexBranch {
+	_, isNumber := char.(walk.ValueNumber)
+	if isNumber {
+		return []SubexBranch{{
+			state: state.next,
+			outputStack: topAppend(outputStack, []walk.Atom{char}),
+			store: store,
+		}}
+	}
+	return nil
+}
+func (state SubexCopyNumberState) accepting(store Store, outputStack OutputStack) []OutputStack {
+	return nil
+}
+
+// Read in a string atom and output it
+type SubexCopyStringAtomState struct {
+	next SubexState
+}
+func (state SubexCopyStringAtomState) eat(store Store, outputStack OutputStack, char walk.Atom) []SubexBranch {
+	_, isStringAtom := char.(walk.StringAtom)
+	if isStringAtom {
+		return []SubexBranch{{
+			state: state.next,
+			outputStack: topAppend(outputStack, []walk.Atom{char}),
+			store: store,
+		}}
+	}
+	return nil
+}
+func (state SubexCopyStringAtomState) accepting(store Store, outputStack OutputStack) []OutputStack {
+	return nil
+}
+
+// Read in an atom and copy it out as long as it is not part of a string
+type SubexCopyNonStringAtomState struct {
+	next SubexState
+}
+func (state SubexCopyNonStringAtomState) eat(store Store, outputStack OutputStack, char walk.Atom) []SubexBranch {
+	_, isStringAtom := char.(walk.StringAtom)
+	_, isStringTerminal := char.(walk.StringTerminal)
+	if isStringAtom || isStringTerminal {
+		return nil
+	}
+	return []SubexBranch{{
+		state: state.next,
+		outputStack: topAppend(outputStack, []walk.Atom{char}),
+		store: store,
+	}}
+}
+func (state SubexCopyNonStringAtomState) accepting(store Store, outputStack OutputStack) []OutputStack {
+	return nil
+}
+
 // Read in any Atom and output it
 type SubexCopyAnyState struct {
 	next SubexState
-- 
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