MATLAB Programming

4 M-File Programming
strcmp str1 str2
ans =
0 (unequal)
% Command syntax
How MATLAB Recognizes Function Calls That Use Command
Syntax
It can be difficult to tell whether a MATLAB expression is a function call
using command syntax or another kind of expression, such as an operation on
one or more variables. Consider the following example:
ls ./d
Is this a call to the ls function with the directory ./d as its argument? Or is it
a request to perform elementwise division on the array that is the value of the
ls variable, using the value of the d variable as the divisor?
This example might appear unambiguous because MATLAB can determine
whether ls and d are functions or variables. But that is not always true.
Some MATLAB components, such as M-Lint and the Editor/Debugger, must
operate without reference to the MATLAB path or workspace. MATLAB
therefore uses syntactic rules to determine when an expression is a function
call using command syntax.
The rules are complicated and have exceptions. In general, when MATLAB
recognizes an identifier (which might name a function or a variable), it
analyzes the characters that follow the identifier to determine what kind of
expression exists. The expression is usually a function call using command
syntax when all of the following are true:
1 The identifier is followed immediately by white space.
2 The characters following the white space are not parentheses or an
assignment operator.
3 The characters following the white space are not an operator that is
itself followed by additional white space and then by characters that can
legitimately follow an operator.
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