Changing the order of execution

25.3.8 Changing the order of execution

The goto command will tell a program to jump to a different spot in a program, where the spot needs to have been marked with label. They both must have the same argument, which is simply a sequence of characters.

label takes mark, a sequence of characters.
label(mark) labels the position in the program with mark.

goto takes mark, a sequence of characters.
goto(mark) goes to the part of the program labeled with mark.

Example

The following program will add the terms of the harmonic series until the term is less than some specified value eps and print the result.

harmsum(eps):={ local S,j; S:=0; j:=0; label(spot); j:=j+1; S:=S+1/j; if (1/j>=eps) goto (spot); print(S); return 0; }