Relation:program
Encapsulate code in a subroutine that can be called with parameters.
Description
program name ((parameter (, parameter...)))
instructionlist
end program
Parameters
name: any valid name
parameter: any valid name
instructionlist: any instruction except function and include.
Examples
Using the sample relation films.csv .
program yearlist(y)
read "films.csv"
select year = y
print
end program
run yearlist(1960)
| film | director | year |
|---|---|---|
| A bout de souffle | Godard | 1960 |
| Tirez sur le pianiste | Truffaut | 1960 |
run yearlist(1962)
| film | director | year |
|---|---|---|
| Cléo de 5 à 7 | Varda | 1962 |
| Jules et Jim | Truffaut | 1962 |
Comments
Programs operate directly on the stack. They do not return a value.
Variable scope: Programs see the global variables outside the program, but if they change their values, they change it only locally, not globally.
Use Name indirection if you want to parametrize also names and not only values.
Use stack if you want to know the columns of the current relation.