From b48dcb0d37bd3db854927df25e6ff41d07501026 Mon Sep 17 00:00:00 2001
From: Charlie Stanton <charlie@shtanton.xyz>
Date: Wed, 19 Apr 2023 13:10:24 +0100
Subject: Combines sum and product into an arithmetic state that contains a
 function for it's operation

Creates arithmetic.go which will house all of these functions
---
 subex/subexstate.go | 123 +++++-----------------------------------------------
 1 file changed, 10 insertions(+), 113 deletions(-)

(limited to 'subex/subexstate.go')

diff --git a/subex/subexstate.go b/subex/subexstate.go
index 6a80eff..cca7a88 100644
--- a/subex/subexstate.go
+++ b/subex/subexstate.go
@@ -2,8 +2,6 @@ package subex
 
 import (
 	"main/walk"
-	"strconv"
-	"errors"
 )
 
 // A state of execution for the transducer
@@ -174,125 +172,24 @@ func (state SubexRangeState) accepting(store Store, outputStack OutputStack) []O
 	return nil
 }
 
-func sumValues(atoms []walk.Atom) (walk.WalkValue, error) {
-	allBools := true
-	var sum float64 = 0
-	var any bool = false
-	values, err := walk.MemoryCompound(atoms)
-	if err != nil {
-		return walk.ValueNull{}, err
-	}
-	for _, value := range values {
-		switch v := value.(type) {
-			case walk.ValueNull:
-				allBools = false
-			case walk.ValueBool:
-				if bool(v) {
-					sum += 1
-					any = true
-				}
-			case walk.ValueNumber:
-				allBools = false
-				sum += float64(v)
-			case walk.ValueString:
-				allBools = false
-				num, err := strconv.ParseFloat(string(v), 64)
-				if err == nil {
-					sum += num
-				} else {
-					return walk.ValueNull{}, errors.New("Tried to sum non-castable string")
-				}
-			default:
-				return walk.ValueNull{}, errors.New("Tried to sum non-number")
-		}
-	}
-	if allBools {
-		return walk.ValueBool(any), nil
-	} else {
-		return walk.ValueNumber(sum), nil
-	}
-}
-
-// At the end of a sum, pops what has been output since the start, sums and outputs it
-// If all values are booleans does OR, if not tries to cast values to numbers to sum them and rejects if values are not castable
-type SubexSumEndState struct {
-	next SubexState
-}
-func (state SubexSumEndState) eat(store Store, outputStack OutputStack, char walk.Atom) []SubexBranch {
-	toSum, newStack := outputStack.pop()
-	sum, err := sumValues(toSum)
-	if err != nil {
-		return nil
-	}
-	return state.next.eat(store, topAppend(newStack, []walk.Atom{sum}), char)
-}
-func (state SubexSumEndState) accepting(store Store, outputStack OutputStack) []OutputStack {
-	toSum, newStack := outputStack.pop()
-	sum, err := sumValues(toSum)
-	if err != nil {
-		return nil
-	}
-	return state.next.accepting(store, topAppend(newStack, []walk.Atom{sum}))
-}
-
-// Compounds atoms into values, if all values are booleans, does AND, if not, tries to cast to numbers and multiply
-func multiplyValues(atoms []walk.Atom) (walk.WalkValue, error) {
-	allBools := true
-	var product float64 = 1
-	var all bool = false
-	values, err := walk.MemoryCompound(atoms)
-	if err != nil {
-		return walk.ValueNull{}, err
-	}
-	for _, value := range values {
-		switch v := value.(type) {
-			case walk.ValueNull:
-				allBools = false
-				product *= 0
-			case walk.ValueBool:
-				if !bool(v) {
-					product *= 0
-					all = false
-				}
-			case walk.ValueNumber:
-				allBools = false
-				product *= float64(v)
-			case walk.ValueString:
-				allBools = false
-				num, err := strconv.ParseFloat(string(v), 64)
-				if err == nil {
-					product *= num
-				} else {
-					return walk.ValueNull{}, errors.New("Tried to sum non-castable string")
-				}
-			default:
-				return walk.ValueNull{}, errors.New("Tried to sum non-number")
-		}
-	}
-	if allBools {
-		return walk.ValueBool(all), nil
-	} else {
-		return walk.ValueNumber(product), nil
-	}
-}
 
-// Does AND or product
-type SubexProductEndState struct {
+type SubexArithmeticEndState struct {
 	next SubexState
+	calculate func([]walk.Atom) ([]walk.Atom, error)
 }
-func (state SubexProductEndState) eat(store Store, outputStack OutputStack, char walk.Atom) []SubexBranch {
-	toMultiply, newStack := outputStack.pop()
-	product, err := multiplyValues(toMultiply)
+func (state SubexArithmeticEndState) eat(store Store, outputStack OutputStack, char walk.Atom) []SubexBranch {
+	toCompute, newStack := outputStack.pop()
+	result, err := state.calculate(toCompute)
 	if err != nil {
 		return nil
 	}
-	return state.next.eat(store, topAppend(newStack, []walk.Atom{product}), char)
+	return state.next.eat(store, topAppend(newStack, result), char)
 }
-func (state SubexProductEndState) accepting(store Store, outputStack OutputStack) []OutputStack {
-	toMultiply, newStack := outputStack.pop()
-	product, err := multiplyValues(toMultiply)
+func (state SubexArithmeticEndState) accepting(store Store, outputStack OutputStack) []OutputStack {
+	toCompute, newStack := outputStack.pop()
+	result, err := state.calculate(toCompute)
 	if err != nil {
 		return nil
 	}
-	return state.next.accepting(store, topAppend(newStack, []walk.Atom{product}))
+	return state.next.accepting(store, topAppend(newStack, result))
 }
-- 
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