### From WeBWorK

# NAME

answerVariableList.pl - Creates answer checkers that compare the student's answer to a list of variable names.

# MACROS

## variable_cmp

ANS(variable_cmp($var_string, %options))

This answer checker compares the student answer to a list of variable names (so, for example, you can ask for what values a given function depends on).

Use `addVariables()`

to create the list of variables that from which
the student can choose, and then use `variable_cmp()`

to generate the
answer checker. If the formula passed to variable_cmp contains
parentheses around the list, then the student's answer must as
well.

You can also include additional parameters to variable_cmp. These
can be any of the flags appropriate for `List()`

answer checker.

Usage examples:

addVariables('x','y','z'); ANS(variable_cmp("(x,y)"));

addVariables('x','y','z','s','t,); ANS(variable_cmp("s,t"));

addVariables('x','y','z'); ANS(variable_cmp("(x)",showHints=>0,showLengthHints=>0));

## addVariables

addVariables(@vars)

Adds each string in @vars as a varible to the current context.