Re: [racket-users] Scribble: line comment swallows paragraph break

[Ben Lerner]

Yes, in that case.  I meant more the following: #lang at-exp racket '@stuff{ Hello@; John           World } which currently produces '(stuff "Hello" "\n" "          " "World"). On 9/17/2015 2:28 PM, Matthew Butterick wrote: > If a comment can swallow everything up to a single newline, could it  > swallow everything up to the first non-whitespace character after the  > current line? (This is what TeX's % does.) Doesn't it already? #lang at-exp racket '@stuff{ Hello@; John           World } '(stuff "HelloWorld") See also [1]:  "all text from the @; to the end of the line and all following spaces (or tabs) are part of the comment (similar to % comments in TeX)." [1] http://pkg-build.racket-lang.org/doc/scribble/reader.html On Thu, Sep 17, 2015 at 8:40 AM, Ben Lerner <bler...@ccs.neu.edu> wrote: If a comment can swallow everything up to a single newline, could it swallow everything up to the first non-whitespace character after the current line?  (This is what TeX's % does.) So you wouldn't have to change scribble/decode at all, just the @-reader.  Effectively, the only added constraint for authors is that a paragraph of text cannot end with a line comment, which seems like a potentially acceptable tradeoff for consistent behavior between TeX and other output formats. On 9/17/2015 11:30 AM, Matthew Flatt wrote: Having a line comment swallow a newline is helpful when you want to break up something in the source without a break in the output, as in Hello@; World => "HelloWorld" I imagine that Eli adopted that feature of @-expressions from TeX. At Thu, 17 Sep 2015 10:59:51 -0400, "Alexander D. Knauth" wrote: I forgot to include the list: On Sep 17, 2015, at 10:57 AM, Alexander D. Knauth <alexan...@knauth.org> wrote: Is there any reason why #lang at-exp racket '@stuff{ Hello @; John World } Shouldn't produce '(stuff "Hello " "\n" "\n" "World") Instead of '(stuff "Hello " "\n" "World") ? In other words, should the newline after the line comment still count as a newline? On Sep 17, 2015, at 10:49 AM, Matthew Flatt <mfl...@cs.utah.edu> wrote: Scribble can't be changed to match LaTeX without changing @-_expression_ reader at a fairly fundamental way, and I'm skeptical of the change. Scribble's input is handled in three steps: @-_expression_ parsing to produce a syntax object (i.e., enriched S-_expression_), Racket expansion and evaluation of the resulting syntax objects to produce values, and (interleaved with the second step) a `scribble/decode` layer that is used by some contexts (including the module body for `scribble/manual`) to find paragraph based on the values produces by the second step. A paragraph is determined at that last step as a pair of newlines separated only by whitespace content. LaTeX handles input in one big character-oriented sweep. In the default mode, it effectively sees a source line that contains only white space (before comment or other handling) and converts it into a `\par`. So, it's detecting paragraphs at a much earlier point than Scribble ---- unless you're in something like a `verbatim` environment, where that character-level handling is changed and blank lines are handled in a different way. Of course, the character-level nature of macros is one of the things that makes TeX macros so powerful, but also one of the things that make them non-composable. For Scribble to define paragraph breaks in terms of blank source lines (i.e., blank before handling comments or other expansions), the notion of paragraph breaks would have to be built into @-_expression_ layer. Since the notion of paragraph breaks doesn't apply to some uses of @-_expression_ notation, paragraph breaks would have to reflected in some different way than, say, inserting `(par)` into the stream as in LaTeX. A syntax property could be attached to a newline to indicate that its source line is blank, but those are fragile (e.g., not preserved in bytecode), and they only work on syntax-object representations of S-expressions. Whatever a better solution might be, I think an even better "solution" is to not to try to solve this problem and keep the @-_expression_ model simpler. At Wed, 16 Sep 2015 18:42:22 -0400, Benjamin Greenman wrote: Scribble and LaTeX disagree on these documents. Should Scribble be changed to match LaTeX? Scribble: #lang scribble/manual Hello @; John World Output is: "Hello World" ;; --- LaTeX \documentclass{article} \begin{document} Hello % John World \end{document} Output is: "Hello World" -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. 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