Passing "0" to boolean option results in "true" value

[ericnewton76]

Issue by ptylenda
Tuesday Sep 20, 2016 at 11:47 GMT
Originally opened as gsscoder/commandline#354

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Define option:

[Option('e', "engineering", SetName = "console", Required = false, HelpText = "Flag whether the build is engineering build")]
        public bool Engineering { get; set; }

When passing "-e 0" to the executable, it results in boolean "true" value, which is unexpected. In conjunction with #353 it results in no possibility to have command line option which would accept 1/0/true/false and work correctly

[ericnewton76]

Comment by anthonylangsworth
Saturday Oct 22, 2016 at 12:01 GMT

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Unfortunately, this appears to be by design, @ptylenda . Take the following example:

[Option('e', "engineering")]
public bool Engineering { get; set; }

[Value(0)]
public int Count { get; set; }

How would the library parse the arguments -e 0? The current master branch sets Engineering to true and Count to 0. Adding the your suggestion would either make the arguments ambiguous or break compatibility with the previous argument parsing result.

Please let me know if I misinterpreted your suggestion.

[ericnewton76]

Comment by Agbar
Wednesday Jan 04, 2017 at 20:13 GMT

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Grammar Details article on wiki explains why it doesn't work as you would expect.
Boolean properties are flags which means value is set (to true) when flag is in command line. -e 0 maps to Engineering set to true and unbound value 0.
If you really need passing true/false/1/0 arguments you can use enum like shown in CommandLine.Demo project and mentioned in Mapping Properties to Options:

enum BooleanValue {false, true}
//...
[Option('e')]
public BooleanValue Engineering { get; set; }

You can use then both -e true or -e 1 in command line.

IMO this issue can be rejected.

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EDIT:
Of course my remarks apply to version 1.9 while this issue seems to regard upcoming v2.