TIP #182 Version 1.2: Add [expr bool] Math Function

This is not necessarily the current version of this TIP.

Abstract

This TIP proposes a new function bool() for use with the [expr] command.

Rationale

This math function would be very useful in a number of different situations, such as:

• if {bool(true)} then { puts "True" }

• if (bool(0x1)} then { puts "True" }

Proposed Change

A new math function named bool would be added to the list of functions supported by the [expr] command.

expr {bool( value )}]

This would return "1" for any value of value that is non-zero (plus all non-numeric strings accepted as true by Tcl_GetBoolean()) and "0" otherwise.

Reference Implementation

A reference implementation does not yet exist. Internally, the function should use something semantically equivalent to using Tcl_GetBoolean().

Copyright

This document has been placed in the public domain.

This is not necessarily the current version of this TIP.