INCLAN: Variable substitutions

There are several ways to insert the value of a variable or the result value of an expression into the command line:

Basic substitutions

Substitutions of the form $variable or %variable insert the complete value of the variable (without trailing blanks) into the command line. Substitutions with “$” differ from those with “%” only if the value of the variable starts and ends with single quotes, i.e. if it is a FORTRAN-77 character constant: with “%” the delimiting single quotes are retained in the substitution, with “$” they are removed. A variable name that is immediately followed by a letter, digit, or underscore character must be enclosed in curly braces: “{$variable}”.

x:=4.6; y:=2.0; sum=x+y; t:=a sum        # set variables
print "This is $t: $x + $y = $sum"       # substitute values
This is a sum: 4.6 + 2.0 = 6.60000

s:=’$t’                           # create a Fortran string from a normal variable
print "\$s = $s; \%s = %s"        # with and without single quotes
$s = a sum, %s = ’a sum’ 
 
print "{$t}mer"
a summer

All substitutions in the command line proceed from right to left. This allows, for example, composition of a variable name from the values of other variables before it is used in a substitution:

command list_param                # user-defined command list_param
  do i 1 nparam
    print "Parameter $i: $p$i"    # $p$i inserts the value of the i-th command line	
                                  # parameter (p1, p2,…).
  end do
end
list_param 17 second last         # call list_param
Parameter 1: 17
Parameter 2: second
Parameter 3: last

Fortran format

Substitutions of the form $variable(format) or %variable(format) are used to format integer or real values of variables according to a FORTRAN-77 format. A format that contains the letter “I” or “i” applies to integer numbers, all other formats to real numbers.

 x:=4.6; y:=2.0; sum=x+y
 print "$x + $y = $sum(E12.3)"
 4.6 + 2.0 =    0.660E+01

Substring

Substitutions of the form $variable(n:m) or %variable(n:m), where n and m are positive integer expressions, are used to substitute with the substring between character positions n and m of the value of a variable. Substring expressions can also appear on the left hand side of assignment statements.

t:=a sum
print "another $t(3:5)"
another sum
t(3:):=program		 # Assignment to a substring
print "$t"
a program

List element

If the value of a variable is a comma-separated list, “ $variable(n)” or “%variable(n)”, where n is a positive integer expression, substitute with the n-th element of this list.

s:=17,28,,56,"This is the end"
do i 1 length(’s’)		 # Length returns the number of elements
  print "Element $i: $s(i)"
end do
Element 1: 17
Element 2: 28
Element 3:
Element 4: 56
Element 5: This is the end

Function call

“$function” or “%function” substitute with the result value of a function without parameters, “$function(parameters)” or “%function(parameters)” substitute with the result value of a function with parameters. If there are several parameters, they are separated by commas.

x=2.5; print "log(x)= $log(x)"
log(x) = 0.916291

Expression

“${expression}” or “%{expression}” substitute with the result value of an expression.

x=2.5; y=10.0; print "x/y = ${x/y}"
x/y = 0.25