NetRexx: Doing things with strings

Doing things with strings

Another thing Rexx is good for is manipulating strings in various ways. NetRexx provides the same facilities as Rexx, but with a syntax that is more like Java or other similar languages:

  phrase='Now is the time for a party'
  say phrase.word(7).pos('r')

The second line here can be read from left to right as "take the variable 'phrase', find the seventh word, and then find the position of the first 'r' in that word". This would display '3' in this case, because 'r' is the third character in 'party'.

(In Rexx, the second line above would have been written using nested function calls:

  say pos('r', word(phrase, 7))

which is not as easy to read; you have to follow the nesting and then backtrack from right to left to work out exactly what's going on.)

In the NetRexx syntax, at each point in the sequence of operations some routine is acting on the result of what has gone before. These routines are called methods, to make the distinction from functions (which act in isolation). NetRexx provides (as methods) most of the functions that were evolved for Rexx, for example:

changestr (change all occurrences of a substring to another)
copies (make multiple copies of a string)
lastpos (find rightmost occurrence)
left and right (return leftmost/rightmost character(s))
reverse (swap end-to-end)
space (pad between words with fixed spacing)
strip (remove leading and/or trailing white space)
pos and wordpos (find the position of string or a word in a string)
verify (check the contents of a string for selected characters)
word, wordindex, wordlength, and words (work with words)

These and the others like them, and the parsing described in the next section, make it especially easy to process text with NetRexx.

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