The ’+’ command can be used like cat (see Section 5.2.12), and the + operator is the infixed version. (See Section 8.3.1 for other uses of + and ’+’.)
Note that + is infixed and ’+’ is prefixed.
| '+'("abcd",3,"d") | 
or:
| "abcd"+3+"d" | 
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| c:=5 | 
then:
| "abcd"+c+"d" | 
or:
| '+'("abcd",c,"d") | 
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