term: add writeln_color()

[kbkpbot]

The PR add write_color() and writeln_color() to term module, enable output ANSI colorful string.

example:

module main
import term
import strings

fn main() {
        mut sb := strings.new_builder(100)
        term.write_color(mut sb, '[Warning]', fg : .red)
        sb.write_string('Please make sure ')
        term.write_color(mut sb, 'value > 0', fg: .cyan)
        sb.write_string(' and ')
        term.write_color(mut sb, 'format is string', fg : .cyan)
        sb.writeln('')

        output := sb.str()
        println(output)
}

will get output:

[huly-for-github]

Connected to Huly®: V_0.6-22833

[Delta456]

But why? We already have term module for that

[spytheman]

I agree with @Delta456 - this should be in term if it is needed, i.e. something like this:

import term
...
term.writeln(mut sb, 'hello', styles :[.bold, .italic, .underline], fg: .red, bg : .cyan)

[kbkpbot]

I agree with @Delta456 - this should be in term if it is needed, i.e. something like this:

import term
...
term.writeln(mut sb, 'hello', styles :[.bold, .italic, .underline], fg: .red, bg : .cyan)

If so, there is a little confuse jump from strings to term and jump back.

a.v

module main
import term
import strings

fn main() {
        mut sb := strings.new_builder(100)
        term.write_color(mut sb, '[Warning]', fg : .red)
        sb.write_string('Please make sure ')
        term.write_color(mut sb, 'value > 0', fg: .cyan)
        sb.write_string(' and ')
        term.write_color(mut sb, 'format is string', fg : .cyan)
        sb.writeln('')

        output := sb.str()
        println(output)
}

And I prefer build the string in string builder, not just output it directly.

[spytheman]

It makes no logical sense for a specific formatting function (using ANSI escape codes) to be part of the string builder.

[spytheman]

And I prefer build the string in string builder, not just output it directly.

I agree - that is why the first argument is a mutable string builder.

That:

term.writeln(mut sb, 'hello', styles :[.bold, .italic, .underline], fg: .red, bg : .cyan)

is a direct equivalent to your:

sb.writeln_color('hello', styles :[.bold, .italic, .underline], fg: .red, bg : .cyan)

It will not print anything on its own to stdout, it will just append to the string builder like yours does.

[spytheman]

@medvednikov what do you think?

[medvednikov]

I agree with spy here