argparse

A submodule to realize parsing of mandatory and optional arguments in batches.

Let's assume that argparse is in same directory as your script. Insert the call in following line to the top (or close to the top, of course) of your batch file and argparse will do the job:

call argparse <options> %*

description

But first things first ...

argparse expects at least the argument options, as a string of mandatory and/or optional arguments, separated by ; (semicolon). Arguments given left of ; are mandatory and right of ; are optional. If no ; is given all arguments are interpreted as mandatory. The order of defined arguments on the left of ; and on the right is irrelevant.

To come back to the example from above, set your options as 1st argument of argparse.

call argparse "-a: -b:;-c:5 -d: -e:point" %*

The arguments need to be defined in options as follows:

• put the options string into quotation marks
• all arguments start with - or --
• all arguments end with :

Mandatory arguments have in addition:

• no default value
• multiple arguments are separated by space e.g.: "--username: --password:"

Optional arguments have in addition:

• a default value
• multiple key-value pairs are separated by space e.g.: "-username:paulo -high:160cm"

Flags:

• are handled same as arguments, but are given without value
• be aware of : at the end of a flag, e.g.: "-q:"
• given flags are set into environment as true; non-existent are set as false
• they can be defined as both mandatory and optional, but it's not allowed to skip an mandatory one

Implementation inspired by this and by this.

usage

call argparse <options> %*

The argument options defines the api interface. The %* forwards all received arguments to argparse. After call of argparse forwarded keys and possible values are set as variables into the environment of the caller. Be aware of already exsistent variables! argparse also deletes variables in the environment of correspondent arguments before running itself.

In case the argument options is "-a: -b:;-c:5 -d: -e:point", argparse will

• expect -a and -b in forwarded arguments and print error if they are not given.
• preset -c to 5, -d (as flag) to true and -e to points. Unknown arguments will cause also an error message. The return errorlevel is on every occured error incremented.

Note that in options a : (colon) is used as delimiter. But in forwarded argmuments space or = (equal sign) is expected, as is usual. Supply the arguments as -key value or as -key=value.

Suppose option is set to

set options="-a: -b:;-c:5 -d: -e:point"

To demonstrate the functionality argmuments are supplied here directly to argparse, but in intended use case they would come from the caller script. Valid calls might be:

a) Only mandatory arguments are specified. The optional ones are preset by default, in this case -d has been set to false.

call argparse %options% -a cherry -b=homes

results in: -a=cherry, -b=homes, -c=5, -d=false, -e=point

b) If a mandatory argument is missing argparse will output an error and increment the errorlevel.

call: argparse %options% -b=homes -c=46

results in: Error: Mandatory argument -a not given, -b=homes, -c=46

c) To improve error handling you might want to add an jump on error using the returned errorlevel. At the label :error you can handle the exception and return with goto :eof if intended or exit completely.

call: argparse %options% -b=homes -c=46 || call :error
goto :sucessful_exit

:error
goto :not_sucessful_exit

See more use cases in test cases or in examples.