scheme@(guile-user)> considered ugly

[Andy Wingo]

Hey all,

I'm thinking that our prompt is really ugly. Sure, it's useful to know
what language and module you're in (though you probably know the
language). But I was just going over some docs and the prompt really
makes it hard to read. The interaction transcript went like this:

     scheme@(guile-user)> (define abc "hello")
     scheme@(guile-user)> abc
     $1 = "hello"
     scheme@(guile-user)> aBc
     <unknown-location>: warning: possibly unbound variable `aBc'
     ERROR: In procedure module-lookup:
     ERROR: Unbound variable: aBc
     Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
     scheme@(guile-user) [1]> (read-options 'help)
     copy              no    Copy source code expressions.
     positions         yes   Record positions of source code expressions.
     case-insensitive  no    Convert symbols to lower case.
     keywords          #f    Style of keyword recognition: #f, 'prefix or 
'postfix.
     r6rs-hex-escapes  no    Use R6RS variable-length character and string hex 
escapes.
     square-brackets   yes   Treat `[' and `]' as parentheses, for R6RS 
compatibility.
     scheme@(guile-user) [1]> (read-enable 'case-insensitive)
     $2 = (square-brackets keywords #f case-insensitive positions)
     scheme@(guile-user) [1]> ,q
     scheme@(guile-user)> aBc
     $3 = "hello"

But what if we elide the language and deparen the module:

     guile-user> (define abc "hello")
     guile-user> abc
     $1 = "hello"
     guile-user> aBc
     <unknown-location>: warning: possibly unbound variable `aBc'
     ERROR: In procedure module-lookup:
     ERROR: Unbound variable: aBc
     Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
     guile-user [1]> (read-options 'help)
     copy              no    Copy source code expressions.
     positions         yes   Record positions of source code expressions.
     case-insensitive  no    Convert symbols to lower case.
     keywords          #f    Style of keyword recognition: #f, 'prefix or 
'postfix.
     r6rs-hex-escapes  no    Use R6RS variable-length character and string hex 
escapes.
     square-brackets   yes   Treat `[' and `]' as parentheses, for R6RS 
compatibility.
     guile-user [1]> (read-enable 'case-insensitive)
     $2 = (square-brackets keywords #f case-insensitive positions)
     guile-user [1]> ,q
     guile-user> aBc
     $3 = "hello"

Is that better? Or is there a better way to make things readable? Like
an extra fresh line before the prompt:

     guile-user> (define abc "hello")

     guile-user> abc
     $1 = "hello"

     guile-user> aBc
     <unknown-location>: warning: possibly unbound variable `aBc'

     ERROR: In procedure module-lookup:
     ERROR: Unbound variable: aBc
     Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
     guile-user [1]> (read-options 'help)
     copy              no    Copy source code expressions.
     positions         yes   Record positions of source code expressions.
     case-insensitive  no    Convert symbols to lower case.
     keywords          #f    Style of keyword recognition: #f, 'prefix or 
'postfix.
     r6rs-hex-escapes  no    Use R6RS variable-length character and string hex 
escapes.
     square-brackets   yes   Treat `[' and `]' as parentheses, for R6RS 
compatibility.

     guile-user [1]> (read-enable 'case-insensitive)
     $2 = (square-brackets keywords #f case-insensitive positions)

     guile-user [1]> ,q

     guile-user> aBc
     $3 = "hello"

But that doesn't look quite right. I have the feeling that the
traditional, minimalist prompt (">") is better, but I'll hold off making
any change for now.

Andy
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