The textwrap crate uses a simpler linear-time algorithm for wrapping
the text. The current algorithm in wrap_help uses several O(n) calls
to String::insert and String::remove, which makes it potentially
quadratic in complexity.
Comparing the 05_ripgrep benchmark at commits textwrap~2 and textwrap
gives this result on my machine:
name before ns/iter after ns/iter diff ns/iter diff %
build_app_long 22,101 21,099 -1,002 -4.53%
build_app_short 22,138 21,205 -933 -4.21%
build_help_long 514,265 284,467 -229,798 -44.68%
build_help_short 85,720 85,693 -27 -0.03%
parse_clean 23,471 22,859 -612 -2.61%
parse_complex 29,535 28,919 -616 -2.09%
parse_lots 422,815 414,577 -8,238 -1.95%
As part of this commit, the wrapping_newline_chars test was updated.
The old algorithm had a subtle bug where it would break lines too
early. That is, it wrapped the text like
ARGS:
<mode> x, max, maximum 20 characters, contains
symbols.
l, long Copy-friendly,
14 characters, contains symbols.
m, med, medium Copy-friendly, 8
characters, contains symbols.";
when it should really have wrapped it like
ARGS:
<mode> x, max, maximum 20 characters, contains
symbols.
l, long Copy-friendly, 14
characters, contains symbols.
m, med, medium Copy-friendly, 8
characters, contains symbols.";
Notice how the word "14" was incorrectly moved to the next line. There
is clearly room for the word on the line with the "l, long" option
since there is room for "contains" just above it.
I'm not sure why this is, but the algorithm in textwrap handles this
case correctly.
Before, inserting a newline did not move the prev_space index forward.
This meant that the next word was measured incorrectly since the
length was measured back to the word before the newly inserted
linebreak.
Fixes#828.
Before, wrapping the help text at, say, 80 characters really meant
that every line could be at most 79 characters wide.
Lines can now be up to and including avail_chars columns wide.
If needed, a desired margin or padding can be subtracted from the
avail_chars argument at a later point.
There are some cases where you need to have an argument to have an
alias, an example could be when you depricate one option in favor of
another one.
Now you are going to be able to alias arguments as follows:
```
Arg::with_name("opt")
.long("opt")
.short("o")
.takes_value(true)
.alias("invisible")
.visible_alias("visible")
```
Closes#669
* feat: adds App::with_defaults to automatically use crate_authors! and crate_version! macros
One can now use
```rust
let a = App::with_defaults("My Program");
// same as
let a2 = App::new("My Program")
.version(crate_version!())
.author(crate_authors!());
```
Closes#600
* imp(YAML Errors): vastly improves error messages when using YAML
When errors are made while developing, the panic error messages have
been improved instead of relying on the default panic message which is
extremely unhelpful.
Closes#574
* imp(Completions): uses standard conventions for bash completion files, namely '{bin}.bash-completion'
Closes#567
* imp(Help): automatically moves help text to the next line and wraps when term width is determined to be too small, or help text is too long
Now `clap` will check if it should automatically place long help
messages on the next line after the flag/option. This is determined by
checking to see if the space taken by flag/option plus spaces and values
doesn't leave enough room for the entirety of the help message, with the
single exception of of if the flag/option/spaces/values is less than 25%
of the width.
Closes#597
* tests: updates help tests to new forced new line rules
* fix(Groups): fixes some usage strings that contain both args in groups and ones that conflict with each other
Args that conflict *and* are in a group will now only display in the
group and not in the usage string itself.
Closes#616
* chore: updates dep graph
Closes#633
* chore: clippy run
* style: changes debug header to match other Rust projects
* chore: increase version
