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2.7 if

The section 2.7 if command allows commands to be executed conditionally.

Syntax:

      if (<condition>) <command-line>

<condition> will be evaluated. If it is true (non-zero), then the command(s) of the <command-line> will be executed. If <condition> is false (zero), then the entire <command-line> is ignored. Note that use of `;` to allow multiple commands on the same line will _not_ end the conditionalized commands.

Examples:

      pi=3
      if (pi!=acos(-1)) print "?Fixing pi!"; pi=acos(-1); print pi

will display:

      ?Fixing pi!
      3.14159265358979

but

      if (1==2) print "Never see this"; print "Or this either"

will not display anything.

See section 2.15 reread for an example of how section 2.7 if and section 2.15 reread can be used together to perform a loop.

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