111 lines
3.4 KiB
Racket
111 lines
3.4 KiB
Racket
#lang scribble/doc
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@(require scribble/manual "utils.rkt" scribble/bnf
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;; "utils.rkt" provides scribble/bnf for-label
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)
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@title[#:tag "bnf"]{BNF Grammars}
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@defmodule[scribble/bnf]{The @racket[scribble/bnf] library
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provides utilities for typesetting grammars.}
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For example,
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@verbatim[#:indent 2]|{
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@(let ([open @litchar{(}]
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[close @litchar{)}])
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@BNF[(list @nonterm{expr}
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@nonterm{id}
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@BNF-seq[open @kleeneplus[@nonterm{expr}] close]
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@BNF-seq[open @litchar{lambda}
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open @kleenestar[@nonterm{id}] close
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@nonterm{expr} close]
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@nonterm{val})
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(list @nonterm{val}
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@BNF-alt[@nonterm{number} @nonterm{primop}])
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(list @nonterm{id}
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@elem{any name except for @litchar{lambda}})])
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}|
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produces the output
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@(let ([open @litchar{(}]
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[close @litchar{)}])
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@BNF[(list @nonterm{expr}
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@nonterm{id}
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@BNF-seq[open @kleeneplus[@nonterm{expr}] close]
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@BNF-seq[open @litchar{lambda}
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open @kleenestar[@nonterm{id}] close
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@nonterm{expr} close]
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@nonterm{val})
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(list @nonterm{val}
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@BNF-alt[@nonterm{number} @nonterm{primop}])
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(list @nonterm{id}
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@elem{any name except for @litchar{lambda}})])
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See also @racket[racketgrammar].
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@defproc[(BNF [prod (cons/c (or/c block? content?)
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(non-empty-listof (or/c block? content?)))]
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...)
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table?]{
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Typesets a grammar table. Each production starts with an element
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(typically constructed with @racket[nonterm]) for the non-terminal
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being defined, and then a list of possibilities (typically constructed
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with @racket[BNF-seq], etc.) to show on separate lines.}
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@defproc[(nonterm [pre-content pre-content?] ...) element?]{
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Typesets a non-terminal: italic in angle brackets.}
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@defproc[(BNF-seq [elem content?] ...) (or/c element? "")]{
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Typesets a sequence.}
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@defproc[(BNF-seq-lines [elems (listof content?)] ...) block?]{
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Typesets a sequence that is broken into multiple lines, where each
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@racket[elems] is one line.}
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@defproc[(BNF-group [pre-content pre-content?] ...) element?]{
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Typesets a group surrounded by curly braces (so the entire group can
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be repeated, for example).}
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@defproc[(optional [pre-content pre-content?] ...) element?]{
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Typesets an optional element: in square brackets.}
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@defproc[(kleenestar [pre-content pre-content?] ...) element?]{
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Typesets a 0-or-more repetition.}
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@defproc[(kleeneplus [pre-content pre-content?] ...) element?]{
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Typesets a 1-or-more repetition.}
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@defproc[(kleenerange [n any/c] [m any/c] [pre-content pre-content?] ...)
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element?]{
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Typesets a @racket[n]-to-@racket[m] repetition. The @racket[n] and
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@racket[m] arguments are converted to a string using @racket[(format
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"~a" n)] and @racket[(format "~a" m)].}
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@defproc[(BNF-alt [elem element?] ...) element?]{
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Typesets alternatives for a production's right-hand side to appear on
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a single line. The result is normally used as a single possibility in
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a production list for @racket[BNF].}
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@; BNF-alt/close is exported but undocumented.
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@; It looks like it produces a more densely packed version of
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@; BNF-alt, but I haven't confirmed this.
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@defthing[BNF-etc element?]{
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An element to use for omitted productions or content.
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Renders as: @BNF-etc
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}
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