$: Index to Facilitate Array and String Operations

When working with arrays or strings $ is the left-hand side linear array index for InlineLoop use.

• When working with Arrays $ is the left-hand side linear array index for InlineLoop use
  • The (global) variable $ is initially set to 1 when a script line is executed
  • The loop terminates at array end or any other error condition
  • The
    block_array
    operation array = F($, ...) is equivalent to
    • DO $ = 1, len_array
    •     array($) = F($, ...)
    • ENDDO
  • vector_elements
    = f(element index):
    • vector = $ ! evaluates to vector = (1,2,3,4,....)
    • vector = ($ - 1) * 1.001 ! set vector to (0.000, 1.001, 2.002, 3.003, ...)
  • factorial_n
    ( execution sequence is $ = 1, 2, 3, ... )
    • REAL :: factorials(n)
    • factorials = *(1:$) ! factorials set to (1, 2, 6, 24, 120, ..., n! )
    • factorial = *(1:n) ! == n!
  • matrix_to_vector
    $ operations:

    DIMENSION vec(100), mtx(4, 4) mtx = $

    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

    vec = mtx($, $) vec = mtx($, $+1) vec = mtx($+1, $)

    1 6 11 16 * * ... 2 7 12 * * * ... 5 10 15 * * * ...

    (* marked elements of vec are out of the $ loop scope, and will not be changed)
  • unity_matrix
    :
    • REAL :: n=33, matrix(n, n)
    • matrix = MOD($, n+1) == 1
    • matrix = $R == $C ! same result, less code
• string_index_operations
  in expressions like string = F($, ...), e.g:
  • • CHARACTER sample_string*20
    • sample_string = CHAR( $ + 64 )
    sets sample_string to "ABCDEFGHIJKLMNOPQRST"
  • • sample_string = "+"($ == $) ! $ to force InlineLoop to execute LEN(sample_string) times, ($==$) is always = 1
    sets sample_string to "++++++++++++++++++++"
  • • sample_string(10*$ -9 : 10*$) = "....+...." // CHAR(48+$)
    sets sample_string to "....+....1....+....2"