feat: Allow disabling negative options by no_negative_options

Also make negative option handling consistent.
Make sure that stcut fields are positive only.

README.md

@@ -257,6 +257,7 @@ Names of fields in the options structure are inferred from the command-line opti
 * The long variant of an option will be mapped to its field name. The short variant will be used only if the long variant is missing.
 * Upper-case letters will converted to lower-case.
 * Dashes (`-`) in an option name will be converted to underscores (`_`) in its field name.
+* No negative names (starting with `no_`). If you want to specify a negative option (the short one using a capital letter and the long one starting with `--no-`), you can, but the field has to be positive and assigned the default value `true`. Then you can detect the presence of the negative option by a comparison to `false`.
 
 If you write a short (single-letter) option for a boolean flag in upper-case, it will set the value `false` to the boolean field instead of `true`. If you write a long option for a boolean flag, you can negate its value by prefixing the option with `no-`:
 
@@ -303,6 +304,7 @@ The following input fields are available:
 | `disable_short_negative` | `bool`      | `false`     | disables handling uppercase letters as negated options       |
 | `ignore_number_overflow` | `bool`      | `false`     | ignores an overflow when converting numbers to option fields |
 | `options_anywhere`       | `bool`      | `false`     | do not look for options only after the line with `Options:`  |
+| `no_negative_options`    | `bool`      | `false`     | do not recognise options starting with `no-` as negations    |
 
 ### Advanced
 
@@ -381,11 +383,15 @@ struct Opts {
 }
 ```
 
-## TODO
+## Contributing
 
-This is a work in progress.
+In lieu of a formal styleguide, take care to maintain the existing coding style. Lint and test your code.
 
-* Add a string map as the parsing target.
+## License
+
+Copyright (c) 2023 Ferdinand Prantl
+
+Licensed under the MIT license.
 
 [VPM]: https://vpm.vlang.io/packages/prantlf.cargs
 [getopt and getopt_long]: https://en.wikipedia.org/wiki/Getopt

src/analyse.v

@@ -12,7 +12,7 @@ mut:
 	val   string
 }
 
-fn analyse_usage(text string, anywhere bool) []Opt {
+fn analyse_usage(text string, anywhere bool, no_negative bool) []Opt {
 	mut re_def := regex_opt('^\\s*-([^\\-])?(?:[|,]\\s*-)?(?:-([^ ]+))?(?:\\s+[<\\[]([^>\\]]+)[>\\]])?') or {
 		panic(err)
 	}
@@ -37,7 +37,7 @@ fn analyse_usage(text string, anywhere bool) []Opt {
 				if grp_opt[2].start >= 0 {
 					opt.val = line[grp_opt[2].start..grp_opt[2].end]
 				}
-				if opt.long.starts_with('no-') {
+				if !no_negative && opt.long.starts_with('no-') {
 					orig_name := opt.long
 					opt.long = opt.long[3..]
 					cargs.d.log('option short: "%s", long: "%s" (originally "%s"), value: "%s"',

src/analyse_test.v

@@ -1,7 +1,7 @@
 module cargs
 
 fn test_no_opts() {
-	opts := analyse_usage('', false)
+	opts := analyse_usage('', false, false)
 	assert opts.len == 0
 }
 
@@ -10,7 +10,7 @@ fn test_no_options_line() {
 Options:
   -l|--line-break     append a line break to the JSON output
 ',
-		true)
+		true, false)
 	assert opts.len == 1
 	assert opts[0].short == 'l'
 	assert opts[0].long == 'line-break'
@@ -22,7 +22,7 @@ fn test_flag() {
 Options:
   -l|--line-break  append a line break to the JSON output
 ',
-		false)
+		false, false)
 	assert opts.len == 1
 	assert opts[0].short == 'l'
 	assert opts[0].long == 'line-break'
@@ -33,7 +33,8 @@ fn test_short_flag() {
 	opts := analyse_usage('
 Options:
   -l  append a line break to the JSON output
-', false)
+', false,
+		false)
 	assert opts.len == 1
 	assert opts[0].short == 'l'
 	assert opts[0].long == ''
@@ -45,19 +46,31 @@ fn test_long_flag() {
 Options:
   --line-break  append a line break to the JSON output
 ',
-		false)
+		false, false)
 	assert opts.len == 1
 	assert opts[0].short == ''
 	assert opts[0].long == 'line-break'
 	assert opts[0].val == ''
 }
 
+fn test_no_negative() {
+	opts := analyse_usage('
+Options:
+  --no-line-break  do not append a line break to the JSON output
+',
+		false, true)
+	assert opts.len == 1
+	assert opts[0].short == ''
+	assert opts[0].long == 'no-line-break'
+	assert opts[0].val == ''
+}
+
 fn test_val() {
 	opts := analyse_usage('
 Options:
   -o|--output <file>  write the JSON output to a file
 ',
-		false)
+		false, false)
 	assert opts.len == 1
 	assert opts[0].short == 'o'
 	assert opts[0].long == 'output'
@@ -68,7 +81,8 @@ fn test_short_val() {
 	opts := analyse_usage('
 Options:
   -o <file>  write the JSON output to a file
-', false)
+', false,
+		false)
 	assert opts.len == 1
 	assert opts[0].short == 'o'
 	assert opts[0].long == ''
@@ -80,7 +94,7 @@ fn test_long_val() {
 Options:
   --output [file]  write the JSON output to a file
 ',
-		false)
+		false, false)
 	assert opts.len == 1
 	assert opts[0].short == ''
 	assert opts[0].long == 'output'

src/parse.v

@@ -14,6 +14,7 @@ pub mut:
 	disable_short_negative bool
 	ignore_number_overflow bool
 	options_anywhere       bool
+	no_negative_options    bool
 }
 
 pub struct Scanned {
@@ -122,7 +123,7 @@ pub fn parse_scanned_to[T](scanned &Scanned, input &Input, mut cfg T) ![]string
 					if d.is_enabled() {
 						d.log_str('flag "${flag}" used')
 					}
-					set_flag(mut cfg, opt, flag)!
+					set_flag(mut cfg, opt, flag, input.no_negative_options)!
 				}
 				applied << opt
 			} else {
@@ -133,7 +134,7 @@ pub fn parse_scanned_to[T](scanned &Scanned, input &Input, mut cfg T) ![]string
 		}
 	}
 
-	check_applied(cfg, applied)!
+	check_applied(cfg, applied, input.no_negative_options)!
 
 	for i < l {
 		cmds << args[i]
@@ -144,7 +145,7 @@ pub fn parse_scanned_to[T](scanned &Scanned, input &Input, mut cfg T) ![]string
 
 pub fn scan(usage string, input &Input) !Scanned {
 	d.log_str('scan command-line usage and fill options')
-	opts := analyse_usage(usage, input.options_anywhere)
+	opts := analyse_usage(usage, input.options_anywhere, input.no_negative_options)
 	raw_args := input.args or { os.args[1..] }
 	args := split_short_opts(opts, raw_args)!
 	return Scanned{opts, args, usage}
@@ -242,7 +243,7 @@ fn split_short_opts(opts []Opt, raw_args []string) ![]string {
 
 fn (opts []Opt) find_opt_and_flag(arg string, input Input) ?(Opt, bool) {
 	mut flag := true
-	name := if arg.starts_with('no-') {
+	name := if !input.no_negative_options && arg.starts_with('no-') {
 		flag = false
 		arg[3..]
 	} else {
@@ -252,10 +253,21 @@ fn (opts []Opt) find_opt_and_flag(arg string, input Input) ?(Opt, bool) {
 	for opt in opts {
 		if name.len == 1 {
 			if name == opt.short {
-				return opt, true
-			} else if !input.disable_short_negative && name[0] < u8(`a`)
-				&& name[0] == opt.short[0] & ~32 {
-				return opt, false
+				flag = if !input.disable_short_negative && !input.no_negative_options
+					&& name[0] < u8(`a`) {
+					false
+				} else {
+					true
+				}
+				return opt, flag
+			} else if !input.disable_short_negative && !input.no_negative_options
+				&& opt.short.len == 1 && name[0] & ~32 == opt.short[0] & ~32 {
+				flag = if name[0] < u8(`a`) {
+					false
+				} else {
+					true
+				}
+				return opt, flag
 			}
 		} else {
 			if name == opt.long {
@@ -283,7 +295,7 @@ fn (opt &Opt) has_name(name string) bool {
 	}
 }
 
-fn check_applied[T](cfg T, applied []Opt) ! {
+fn check_applied[T](cfg T, applied []Opt, no_negative bool) ! {
 	mut valid := []Opt{}
 
 	$for field in T.fields {
@@ -309,7 +321,7 @@ fn check_applied[T](cfg T, applied []Opt) ! {
 		mut found := false
 		for opt in applied {
 			name := opt.field_name()
-			if name == arg_name {
+			if name == field.name || opt.long == arg_name {
 				valid << opt
 				found = true
 				break
@@ -347,7 +359,7 @@ fn set_val[T](mut cfg T, opt Opt, val string, input Input) ! {
 			}
 		}
 
-		if name == arg_name {
+		if name == field.name || opt.long == arg_name {
 			ino := nooverflow || input.ignore_number_overflow
 
 			if d.is_enabled() {
@@ -452,7 +464,7 @@ fn convert_val[T](val string, ignore_overflow bool) !T {
 	}
 }
 
-fn set_flag[T](mut cfg T, opt Opt, flag bool) ! {
+fn set_flag[T](mut cfg T, opt Opt, flag bool, no_negative bool) ! {
 	name := opt.field_name()
 	$for field in T.fields {
 		mut arg_name := field.name
@@ -462,7 +474,7 @@ fn set_flag[T](mut cfg T, opt Opt, flag bool) ! {
 			}
 		}
 
-		if name == arg_name {
+		if name == field.name || opt.long == arg_name {
 			if d.is_enabled() {
 				d.log_str('setting flag "${name}" using argument "${arg_name}" to "${flag}"')
 			}

src/parse_test.v

@@ -10,6 +10,18 @@ struct TwoTrue {
 	output     string
 }
 
+struct TwoNegative {
+	no_line_break bool
+}
+
+struct TwoPositiveTrue {
+	line_break bool = true
+}
+
+struct TwoPositiveFalse {
+	line_break bool
+}
+
 fn test_no_opts_no_args() {
 	opts, args := parse[Two]('', Input{ args: [] })!
 	assert opts.line_break == false
@@ -62,6 +74,33 @@ fn test_no_options_line() {
 	assert opts.line_break == true
 }
 
+fn test_no_negative_options() {
+	opts, args := parse[TwoNegative]('
+Options:
+  -n|--no-line-break  do not append a line break to the JSON output
+',
+		Input{ args: ['-n'], no_negative_options: true })!
+	assert opts.no_line_break == true
+}
+
+fn test_negative_option() {
+	opts, args := parse[TwoPositiveTrue]('
+Options:
+  -N|--no-line-break  do not append a line break to the JSON output
+',
+		Input{ args: ['-N'] })!
+	assert opts.line_break == false
+}
+
+fn test_positive_option() {
+	opts, args := parse[TwoPositiveFalse]('
+Options:
+  -N|--no-line-break  do not append a line break to the JSON output
+',
+		Input{ args: ['-n'] })!
+	assert opts.line_break == true
+}
+
 fn test_neg_short_flag() {
 	opts, args := parse[Two]('
 Options: