Re: [Chicken-hackers] substring function and bounds checks

[Alex Shinn]

Hi,

On Thu, Feb 7, 2013 at 3:20 AM, Michele La Monaca <address@hidden> wrote:

[..] I don't think

(substring2 "foo" 0 10) -> "foo"

is conceptually wrong or sloppy as long as you know exactly what the
semantic of the function is ("give me at most N chars" -> perl or
"give me chars up to the Nth position or up to the end of the string
whatever the first" -> python, ruby).

Truncating a string to a maximum length is a common

operation for formatting - I was surprised there was no

easy way to do this with SRFI-13.  But in this case the

start argument isn't needed and distracting.  You probably

want something like:

  (string-truncate "foo" 10) => "foo"

  (string-truncate "foofoofoofoo" 10) => "foofoofoof"

In the fmt egg:

  (fmt #f (trim 10 "foo")) => "foo"

Conflating this with substring is confusing and hides

potential errors, as others have pointed out.

-- 

Alex