How to split a variable into an array in batch - arrays

Question

I'm trying to write a text adventure in batch, so I want to know how I can split variable like set userinput=take book and turn it into an array. I want to be able to write a program that will split strings into array items at each space. I've done this in a lot of other languages. There are several other questions like this, but I don't feel like they answer my question.

Answer 1

This task is probably much more difficult than you realize. There are lots of "simple" methods, but none of the simple ones are robust.
For example, a simple FOR loop can parse out individual tokens, but it will be broken by *, ?, and possibly ".
A robust solution requires a significant amount of code.
Here is my solution, with extensive comments:
#echo off
:: Start out with delayed expansion disabled, and define "user input"
:: I intentionally include "problem" characters
setlocal disableDelayedExpansion
set "userinput=take book! & ;MustPreserve EmptyLinesAreIgnored"
:: Initialize count
set "cnt=0"
:: Enable and use delayed expansion to protect against poison characters
setlocal enableDelayedExpansion
:: Substitute <LineFeed> for each <space>
(set parsed=!userinput: =^
%= Do not remove or alter this line =%
!)
:: Iterate each line, setting delims and eol to <space> to preserve all tokens
for /f "eol= delims= " %%A in ("!parsed!") do (
%= Return to delayed expansion disabled on first iteration, else ! is lost =%
if "!" equ "" endlocal
%= Increment the count =%
set /a cnt+=1
%= Temporarily enable delayed expansion to capture current count in FOR variable =%
setlocal enableDelayedExpansion
for %%N in (!cnt!) do (
endlocal
%= Save the array value =%
set "token.%%N=%%A"
)
)
::Print the results. Safe array access requires delayed expansion
setlocal enableDelayedExpansion
for /l %%N in (1 1 !cnt!) do echo token.%%N=!token.%%N!
It looks a bit better without all the comments
#echo off
setlocal disableDelayedExpansion
set "userinput=take book! & :MustPreserveColon ;MustPreserve EmptyLinesAreIgnored"
set "cnt=0"
setlocal enableDelayedExpansion
(set parsed=!userinput: =^
%= Do not remove or alter this line =%
!)
for /f "eol= delims= " %%A in ("!parsed!") do (
if "!" equ "" endlocal
set /a cnt+=1
setlocal enableDelayedExpansion
for %%N in (!cnt!) do (
endlocal
set "token.%%N=%%A"
)
)
setlocal enableDelayedExpansion
for /l %%N in (1 1 !cnt!) do echo token.%%N=!token.%%N!
And here is the output:
token.1=take
token.2=book!
token.3=&
token.4=;MustPreserve
token.5=EmptyLinesAreIgnored