NAME

XAO::DO::Web::Math - calculate and output a value

SYNOPSIS

 <%Math formula='{x}+{y}' value.x='2' value.y='3'%>

DESCRIPTION

Given a formula and some values calculates the result and displays it optionally formatting according to the given format:

 <%Math formula='{x}+{y}' value.x='2' value.y='3'%>
    -- output '5'

 <%Math formula='1/{x}' value.x='3' format='%.3'%>
    -- output '0.333'

 <%Math formula='1 / ({a} - {b})' value.a='7' value.b='7' default='-'%>
    -- output '-'

Formulas should not be received from untrusted sources. They are 'eval'ed to calculate the result. Some care is taken to avoid illegal formulas, but there are no guarantees.

When an operation cannot be performed (division by zero for instance) the result is 'default' value or empty if not set. Illegal arguments, such as non-numeric, produce the same result.

If a 'path' or 'template' is given then the result is shown in that template with the following parameters:

  FORMULA   => formula with substituted values, as calculated
  RESULT    => calculation result
  ERROR     => error message if calculation could not be performed
  ERRCODE   => more concise error code (FORMULA, VALUE, FUNCTION, CALCULATE)

Some mathematical functions are also supported: min(), max(), sum(), abs(), and sqrt(). The first three work on any number of arguments.

METHODS

EXPORTS

Nothing.

AUTHOR

Copyright (c) 2012 Andrew Maltsev

<am@ejelta.com> -- http://ejelta.com/xao/

SEE ALSO

Recommended reading: XAO::Web, XAO::DO::Web::Page.