Re: [sr-dev] git:andrei/rve_f_params: NEWS: notes about expressions in function parameters
12 Aug
2010
12 Aug
'10
9:26 a.m.
forgot to cc the list...
Am 11.08.2010 20:11, schrieb Andrei Pelinescu-Onciul:
On Aug 11, 2010 at 18:39, Klaus
Darilion<klaus.mailinglists(a)pernau.at> wrote:
I can't remember if I was for or against a dedicated concat parameter,
but now I think a dedicated parameter would be good. '.' might be
confusing as well once we support float numbers.
Is it possible to analyze how sr evaluates the term?
regards
klaus
Am 11.08.2010 17:19, schrieb Andrei Pelinescu-Onciul:
f("7 + 6 = 76") :-)
but
f("7 +" +" 6 = " + (7 + 6)) is f("7 + 6 = 13"), as
expected.
I agree it's confusing, but when I wanted to add a separate operator for
string concat (e.g. '.') lots of people opposed it on the grounds that
it will be too difficult for a script writer to use 2 different operators
(or something similar).
Now we have auto-conversion everywhere...
Maybe we can revisit this and the option of declaring only typed
variable for a future release. On Aug 11, 2010 at 17:13, Klaus
Darilion<klaus.mailinglists(a)pernau.at> wrote:
... + 7 * 6)
^ ^
| |
A B
IMO it is very confusing (if not even wrong) that A is a string
concat and B is a arithmetic operation. What happens with:
... + 7 + 6) ? Hi Andrei!
Am 11.08.2010 16:18, schrieb Andrei Pelinescu-Onciul:
> + - all the module functions can now be called with any constant expression
> + as parameters. E.g.: f("7 *" +" 6 = " + 7 * 6);
What is the result of this example?
f("7 * 6 = 42") 
13 Aug
13 Aug
11:11 a.m.
New subject: git:andrei/rve_f_params: NEWS: notes about expressions in function parameters
On Aug 12, 2010 at 09:26, Klaus Darilion <klaus.mailinglists(a)pernau.at> wrote:
forgot to cc the list...
Am 11.08.2010 20:11, schrieb Andrei Pelinescu-Onciul:
f("7 + 6 = " + 7 + 6) =>
since '+' has the same priority:
("7 + 6 = " + 7) + 6 =>
("7 + 6 = " + (str) 7) + 6 [first term is str => forces str
conversion]
("7 + 6 = 7" + 6) =>
("7 + 6 = 7" + (str)6) =>
"7 + 6 = 76"
In the '*' case:
("7 + 6 = " + 7 * 6)
'*' has higher prio then '+' =>
("7 + 6 = " + (7*6)) =>
("7 + 6 = " + 42 ) ...
The '+' operator is special in the sense that it converts its right
operand to the type of the left operand and the result also has the type
of the left operand. The other operators force conversion
and always have a fixed return type (e..g '*' converts both of its
operands to int and always returns int).
More examples:
"1" + 2 = "12"
1 + "2" => error
"1" + "2" = "12"
"1" * 2 => error
1 * "2" => error
"1" * "2" => error
(int)"1" * 2 = 2
Note also that the code internally supports a CONCAT operator (that
works only on strings) and IPLUS operator (+ for integers only). Right
now they are used in optimizations (when possible the PLUS operator is
replaced during the optimization phase with either CONCAT or IPLUS).
They could easily be enabled from cfg.y (if we find a "name" for them).
Andrei
On Aug 11, 2010 at 18:39, Klaus
Darilion<klaus.mailinglists(a)pernau.at> wrote:
I can't remember if I was for or against a dedicated concat
parameter, but now I think a dedicated parameter would be good. '.'
might be confusing as well once we support float numbers.
Is it possible to analyze how sr evaluates the term?
Am 11.08.2010 17:19, schrieb Andrei Pelinescu-Onciul:
f("7 + 6 = 76") :-)
but
f("7 +" +" 6 = " + (7 + 6)) is f("7 + 6 = 13"), as
expected.
I agree it's confusing, but when I wanted to add a separate operator for
string concat (e.g. '.') lots of people opposed it on the grounds that
it will be too difficult for a script writer to use 2 different operators
(or something similar).
Now we have auto-conversion everywhere...
Maybe we can revisit this and the option of declaring only typed
variable for a future release. On Aug 11, 2010 at 17:13, Klaus
Darilion<klaus.mailinglists(a)pernau.at> wrote:
>Hi Andrei!
>
>Am 11.08.2010 16:18, schrieb Andrei Pelinescu-Onciul:
>>+ - all the module functions can now be called with any constant expression
>>+ as parameters. E.g.: f("7 *" +" 6 = " + 7 * 6);
>
>What is the result of this example?
f("7 * 6 = 42")
... + 7 * 6)
^ ^
| |
A B
IMO it is very confusing (if not even wrong) that A is a string
concat and B is a arithmetic operation. What happens with:
... + 7 + 6) ?
1:14 p.m.
New subject: git:andrei/rve_f_params: NEWS: notes about expressions in function parameters
Am 13.08.2010 11:11, schrieb Andrei Pelinescu-Onciul:
The '+' operator is special in the sense that
it converts its right
operand to the type of the left operand and the result also has the type
of the left operand. The other operators force conversion
and always have a fixed return type (e..g '*' converts both of its
operands to int and always returns int).
More examples:
"1" + 2 = "12"
1 + "2" => error
"1" + "2" = "12"
"1" * 2 => error
1 * "2" => error
"1" * "2" => error
Why are these errors? You said "The other operators force conversion"
regards
klaus
(int)"1" * 2 = 2
1:22 p.m.
New subject: git:andrei/rve_f_params: NEWS: notes about expressions in function parameters
On Aug 13, 2010 at 13:14, Klaus Darilion <klaus.mailinglists(a)pernau.at> wrote:
Am 13.08.2010 11:11, schrieb Andrei Pelinescu-Onciul:
Sorry I should have said "expects and converts only if '+' and target
type is string". strings are never converted to integers unless an
explicit cast is used (e.g. (int)"1").
Andrei
The '+' operator is special in the sense
that it converts its right
operand to the type of the left operand and the result also has the type
of the left operand. The other operators force conversion
and always have a fixed return type (e..g '*' converts both of its
operands to int and always returns int).
More examples:
"1" + 2 = "12"
1 + "2" => error
"1" + "2" = "12"
"1" * 2 => error
1 * "2" => error
"1" * "2" => error
Why are these errors? You said "The other operators force conversion"
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3 comments
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Andrei Pelinescu-Onciul -
Klaus Darilion