From c19df3ff75e7693e38940f20a5f3b40931be424a Mon Sep 17 00:00:00 2001
From: Charlie Stanton <charlie@shtanton.xyz>
Date: Fri, 23 Dec 2022 15:53:24 +0000
Subject: Changes main to read input from stdin. Prunes states that won't
 wouldn't ever reach the front of the state priority queue.

---
 main/main.go     | 34 ++++++++++++++++++++++++++++------
 main/subexast.go | 20 ++++++++++----------
 2 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/main/main.go b/main/main.go
index 0466371..cc671ee 100644
--- a/main/main.go
+++ b/main/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	"os"
 	"fmt"
+	"io"
 )
 
 type TransducerOutput interface {
@@ -53,6 +54,23 @@ func (pair SubexBranch) accepting() []string {
 	return pair.state.accepting(pair.store)
 }
 
+func equalStates(left SubexBranch, right SubexBranch) bool {
+	// Only care about if they are the same pointer
+	return left.state == right.state
+}
+
+func pruneStates(states []SubexBranch) (newStates []SubexBranch) {
+	outer: for _, state := range states {
+		for _, newState := range newStates {
+			if equalStates(state, newState) {
+				continue outer
+			}
+		}
+		newStates = append(newStates, state)
+	}
+	return newStates
+}
+
 func runTransducer(transducer SubexState, input string) (output string, err bool) {
 	states := []SubexBranch{{
 		state: transducer,
@@ -64,7 +82,7 @@ func runTransducer(transducer SubexState, input string) (output string, err bool
 		for _, state := range states {
 			newStates = append(newStates, state.eat(char)...)
 		}
-		states = newStates
+		states = pruneStates(newStates)
 	}
 	for _, state := range states {
 		outputEnds := state.accepting()
@@ -76,16 +94,20 @@ func runTransducer(transducer SubexState, input string) (output string, err bool
 }
 
 func main() {
-	if len(os.Args) != 3 {
-		panic("Expected: program [input] [subex]")
+	if len(os.Args) != 2 {
+		panic("Expected: program [subex]")
+	}
+	inputBytes, inputErr := io.ReadAll(os.Stdin)
+	input := string(inputBytes)
+	if inputErr != nil {
+		fmt.Println("Error reading")
 	}
-	input := os.Args[1]
-	program := os.Args[2]
+	program := os.Args[1]
 	ast := parse(program)
 	transducer := compileTransducer(ast)
 	output, err := runTransducer(transducer, input)
 	if err {
 		output = input
 	}
-	fmt.Println(output)
+	fmt.Print(output)
 }
diff --git a/main/subexast.go b/main/subexast.go
index 510335f..040bc9d 100644
--- a/main/subexast.go
+++ b/main/subexast.go
@@ -23,8 +23,8 @@ type SubexASTStore struct {
 	slot rune
 }
 func (ast SubexASTStore) compileWith(next SubexState) SubexState {
-	return SubexStoreState {
-		match: ast.match.compileWith(SubexNoneState{}),
+	return &SubexStoreState {
+		match: ast.match.compileWith(&SubexNoneState{}),
 		slot: ast.slot,
 		next: next,
 	}
@@ -37,7 +37,7 @@ type SubexASTOr struct {
 	first, second SubexAST
 }
 func (ast SubexASTOr) compileWith(next SubexState) SubexState {
-	return SubexGroupState {
+	return &SubexGroupState {
 		ast.first.compileWith(next),
 		ast.second.compileWith(next),
 	}
@@ -79,7 +79,7 @@ type SubexASTRepeat struct {
 }
 func (ast SubexASTRepeat) compileWith(next SubexState) SubexState {
 	for i := ast.min; i < ast.max; i += 1 {
-		next = SubexGroupState {
+		next = &SubexGroupState {
 			ast.content.compileWith(next),
 			next,
 		}
@@ -92,7 +92,7 @@ func (ast SubexASTRepeat) compileWith(next SubexState) SubexState {
 
 type SubexASTCopyRune rune
 func (ast SubexASTCopyRune) compileWith(next SubexState) SubexState {
-	return SubexCopyRuneState{
+	return &SubexCopyRuneState{
 		rune: rune(ast),
 		next: next,
 	}
@@ -100,7 +100,7 @@ func (ast SubexASTCopyRune) compileWith(next SubexState) SubexState {
 
 type SubexASTCopyAny struct {}
 func (ast SubexASTCopyAny) compileWith(next SubexState) SubexState {
-	return SubexCopyAnyState{next}
+	return &SubexCopyAnyState{next}
 }
 func (ast SubexASTCopyAny) String() string {
 	return "."
@@ -110,7 +110,7 @@ type SubexASTOutput struct {
 	replacement []TransducerOutput
 }
 func (ast SubexASTOutput) compileWith(next SubexState) SubexState {
-	return SubexOutputState{
+	return &SubexOutputState{
 		content: ast.replacement,
 		next: next,
 	}
@@ -120,7 +120,7 @@ type SubexASTTry struct {
 	content SubexAST
 }
 func (ast SubexASTTry) compileWith(next SubexState) SubexState {
-	return SubexGroupState {
+	return &SubexGroupState {
 		ast.content.compileWith(next),
 		next,
 	}
@@ -130,7 +130,7 @@ type SubexASTMaybe struct {
 	content SubexAST
 }
 func (ast SubexASTMaybe) compileWith(next SubexState) SubexState {
-	return SubexGroupState {
+	return &SubexGroupState {
 		next,
 		ast.content.compileWith(next),
 	}
@@ -146,7 +146,7 @@ func (ast SubexASTJoin) compileWith(next SubexState) SubexState {
 	}
 	manyContentsState := ast.content.compileWith(afterContentState)
 	afterContentState.first = ast.delimiter.compileWith(manyContentsState)
-	return SubexGroupState {
+	return &SubexGroupState {
 		manyContentsState,
 		next,
 	}
-- 
cgit v1.2.3