1GENERAL: eval, show, set - set and show the values of variables

Usage: eval <variable> = <expression>
       show {<variable>}
       set {<variable>}
       set <variable> = <value>
       <variable> = <expression>
       <variable> := <expression>

The "eval" statement evaluates the Fortran-77 <expression> and assigns the
result to the <variable>.

The statement "show" without parameters lists the names and values of all 
global variables that do not have the value "NULL"; with parameters, "show"
lists the names and values of the given variables. Global variables that are
hidden by a local variable with the same name are identified by the attribute
"hidden". Read-only variables are identified by the attribute "read-only".

The statement "set" without parameters lists the names and values of all
variables that do not have the value "NULL"; with parameters, "set" lists
the names and values of the given variables. In contrast to "show", local
variables are listed too. Read-only variables are identified by the attribute
"read-only".

"set <variable> = <value>" gives the variable <variable> the string value 
<value>.

"<variable> = <expression>" and "<variable> := <expression>" are shorthand
notations for "eval <variable> = <expression>" and "set <variable> =
<expression>", respectively. Note that these shorthand notations require
a blank before and after the "=" or ":=".

Examples: set i=7
          eval j=mod(i,4)**2
          string := 'Halb so teuer, doppelt so gut.'
          length = len(string)
          set i j string length
          ... Variables:
              i      = 7
              j      = 9
              string = 'Halb so teuer, doppelt so gut.'
              length = 30

See also: var, variable