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Added a simple lexer. #4
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This lexer will parse programs, skipping unknown characters, and collapsing repeated occurrences of identical tokens. The result will be a stream of values which can be compiled.
I've updated the lexer to skip newlines/unknown characters, and avoid handling repeated loop open/closes - since we need to count those separately. We're now using the lexer in our generation and that is good.
Oftentimes brainfuck programs are formatted in a "readable" fashion
with newlines, and spaces. If we have an input-program that
looks like this:
> ---------------------------------
> ---------------------------------
> +++----
We'd parse that naively as:
> {Type: "-", Repeat: X}
> {Type: "-", Repeat: X}
> {Type: "+", Repeat: X}
> {Type: "-", Repeat: X}
i.e. The first two lines would count as two tokens. If we remove
the newlines before we process the input we instead get:
> {Type: "-", Repeat: X}
> {Type: "+", Repeat: X}
> {Type: "-", Repeat: X}
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This pull-request, once complete, will replace our inline parsing with a standalone brainfuck lexer.
The lexer will produce a stream of tokens, along with a count of how many times those tokens were seen repeated.
So given an input string of "
<<<<<>>>>>" we'll expect to see:{Type: "<", Repeat: 5}{Type: ">", Repeat: 5}{Type: EOF, Repeat: 1}Trivial cases added too, but not exhaustively. This will close #3.