plusto operator definition missing?

[chris hermansen]

Hello all,

I was going through Lindsey a couple of days ago and noticed the plusto
operator definition on p. 244.  Here is what it says:

operator priority mode of a  mode of b  mode of result  meaning
plusto       1      string  ref string    ref string   b := a + b
+=:                  char   ref string    ref string

(I hope that shows up ok in peoples' email; I did it in fixed width text)

I have a version of the procedure "whole" that I use with GNU Algol 68 that
has the line

digit_string := digit_char + digit_string

in it, and I thought I'd try +=: instead, as in:

digit_string +=: digit_char

However, ga68 complains:

testl.a68:277:50: error: CHAR cannot be coerced to REF STRING in this
context
  277 |                                 digit_string +=: digit_char;

I am supposing that this is due to not having the second version of the
operator defined - the one that works with a char on the right hand side.

Am I missing something?  Thanks in advance.

-- 
Chris Hermansen · clhermansen "at" gmail "dot" com

C'est ma façon de parler.
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