OpenEuphoria

2. Re: Two possible bugs in docs!

• Posted by "Graeme." <hmi at POWERUP.COM.AU> Jun 20, 1998
• 725 views

At 08:54 AM 6/19/98 -0400, Alan wrote something.

Despite the smoewhat off-topic heading for
this message, I believe you are looking
for clarification on 1) for loops and
2) using variable types as functions.


1) For loops


>include file.e
>
>integer fn
>fn = open("mydata", "r")         --<opens file
>
>-- read and display first line of file 3 times:
>
>for i = 1 to 3 do                --<declares i = 1
>    puts(1, gets(fn))            --<gets and displays a line
>    if seek(fn, 0) then          --<rewinds to offset 0
>        puts(1, "rewind failed!\n")
>    end if
>end for                          --<i=i+1 do it again until i=3


The variable i is declared when the for loop
is declared and exists only inside the loop.
This loop executes 3 times, so the code inside
it is repeated 3 times.

Try this:

for number=0 to 9 do
    puts(1,"\nnumber :")
    print(1,number)
end for


2) Using Types as Functions

A type such as atom and integer or a
user defined type can be called like
a normal function to check a value
against the defined limits of the type.

>              line = gets(0)
>              if atom(line) then
>                  puts(SCREEN, "end of file\n")
>              end if

the second line here means:

If the variable "line" is an atom then...

The gets() function will return a
sequence unless it reaches the end of
file, when it will return -1 (an atom),

So if variable "line" is an atom and not
a sequence then the end of the file has been
reached.

Graeme.





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