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 ++++++++++++++++++++++++++++------
 1 file changed, 28 insertions(+), 6 deletions(-)

(limited to 'main/main.go')

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)
 }
-- 
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