MATLAB Programming

4 M-File Programming
This section covers the following topics
• “Defining a Specification for Each Input Parameter” on page 4-38
• “Parsing Parameter Values on the Function Call” on page 4-41
• “Packaging Arguments in a Structure” on page 4-42
• “Arguments That Default” on page 4-44
• “Validating the Input Arguments” on page 4-44
• “Making a Copy of the Schema” on page 4-47
• “Summary of inputParser Methods” on page 4-47
• “Summary of inputParser Properties that Control Parsing” on page 4-47
• “Summary of inputParser Properties that Provide Information” on page
4-48
To illustrate how to use the inputParser class, the documentation in this
section develops a new M-file program called publish_ip, (based on the
MATLAB publish function). There are three calling syntaxes for this
function:
publish_ip('script')
publish_ip('script', 'format')
publish_ip('script', options)
There is one required argument (script), one optional argument (format),
and a number of optional arguments that are specified as parameter-value
pairs (options).
Defining a Specification for Each Input Parameter
Most programs have a block of code toward the beginning that parses the
values in the input argument list and checks these values against what is
expected. The inputParser classprovidesthefollowingmethodswithwhich
you can specify what the inputs are and whether they are required, optional,
or to be specified using the parameter-value syntax:
• addRequired — Add a required parameter to the schema
• addOptional — Add an optional parameter to the schema
4-38