Using INCLAN variables

In INCLAN, string variables can be used in a similar way as in a Unix shell:

cyana> name:=Cyana
cyana> print "My name is $name."
My name is Cyana.

The operator “:=” assigns a string (“Cyana”) to a variable (“name”). $variable substitutes the value of a variable into the command line. In addition, variables with numeric values can be used in expressions in the same way as in Fortran or other programming languages:

cyana> x=7
cyana> y=5*x
cyana> z=sqrt(y-10.0)
cyana> show x y z
    x = 7
    y = 35
    z = 5.0

(The INCLAN command show displays the values of variables.) Here a different assignment sign, “=” instead of “:=”, was used. Assignments with “=” have the meaning: “Evaluate the expression on the right hand side and assign the result value to the variable on the left hand side.” Note the difference to a string assignment with “:=”:

cyana> y:=5*x
cyana> show y
    y = 5*x
cyana> y=5*x
cyana> show y
    y = 35

Expressions formed according to the rules of Fortran-77 may contain integer, real and complex numbers, logicals (Boolean values), and character strings. Within expressions character strings must be enclosed in single quotes:

cyana> s:=cyana
cyana> l=lenstr(s)
*** ERROR: Illegal expression "lenstr(s)".

This is an error because the variable s does not contain a quoted string (lenstr is an INCLAN function that returns the length of a string, i. e. the index of its last non-blank character). The correct use of simple, unquoted strings in an expression is:

cyana> l=lenstr('$s')
cyana> show l
    l = 5

Single quotes do not inhibit variable substitutions.