[go-nuts] When ignoring error or any other function return parameters, is there another way to write this 2 lines of code?

On Fri, Nov 22, 2013 at 8:46 AM, Danilo Cabello wrote:

I have this 2 lines of code:

parsedCapacity, _ := strconv.ParseInt(formCapacity, 10, 0)
capacity := int(parsedCapacity)

As you can see I am ignoring the second return parameter, the error,
parsedCapacity is int64 and for simplicity I am casting capacity to int.

Is there any other way to write this 2 lines of code?

parsedCapacity for me acts like a temporary variable, I would like to be
able to do the conversion and casting without having to maintain this
temporary variable of undesirable type.

On Friday, 22 November 2013 11:46:24 UTC-5, Danilo Cabello wrote:

Hi,

I have this 2 lines of code:

parsedCapacity, _ := strconv.ParseInt(formCapacity, 10, 0)
capacity := int(parsedCapacity)

As you can see I am ignoring the second return parameter, the error,
parsedCapacity is int64 and for simplicity I am casting capacity to int.

Is there any other way to write this 2 lines of code?

parsedCapacity for me acts like a temporary variable, I would like to be
able to do the conversion and casting without having to maintain this
temporary variable of undesirable type.

Am Freitag, 22. November 2013 18:09:15 UTC+1 schrieb Robert Johnstone:
It the pattern occurs repeatedly, and you are confident that ignoring the
error is safe, you could wrap strconv.ParseInt in a function. There is a
convention of prefixing functions that ignore errors with "Must".

On Wed, Nov 27, 2013 at 10:50 AM, Harald Weidner wrote:

Am Freitag, 22. November 2013 18:09:15 UTC+1 schrieb Robert Johnstone:

In most of my programs, I define a generic "must" function that strips off
the error and returns the other return value.

http://play.golang.org/p/KJkKs1d6l7

This allows to concatenate function calls even when they return an error as
a second return value. It is especially useful in web applications, where a
proper panic handler is already present.

The drawback is, however, that a type assertion is needed for the result,
unless it is passed to a function which takes interface{} arguments (like
fmt.Println).

IMO, the "Must" pattern is so idiomatic that Go should provide a builtin
must() function which does the same, but for a variadic number of parameters
before the error, and without type assertion (by type inheritance). Just my
opinion...

Harald

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On Tuesday, November 26, 2013 5:00:11 PM UTC-7, Dave Cheney wrote:
the
a
I disagree. Adding a must() builtin function would send the wrong
message that Go favours panics over explicit error handling.

Cheers

Dave

Not to mention that while `func Must(i int, _ error) { return i }` can be
inlined and potentially result in a nop, the aforementioned generic Must
implementation is only generic for two-argument inputs, and more
importantly, the cost of boxing/unboxing at runtime is extremely high
considering you're only saving one line of code, and that most gophers have
learned to embrace the idea that, even when all else is equal, a one-line
savings is no savings at all.
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On Friday, November 22, 2013 6:46:24 PM UTC+2, Danilo Cabello wrote:

Hi,

I have this 2 lines of code:

parsedCapacity, _ := strconv.ParseInt(formCapacity, 10, 0)
capacity := int(parsedCapacity)

As you can see I am ignoring the second return parameter, the error,
parsedCapacity is int64 and for simplicity I am casting capacity to int.

Is there any other way to write this 2 lines of code?

parsedCapacity for me acts like a temporary variable, I would like to be
able to do the conversion and casting without having to maintain this
temporary variable of undesirable type.

Thanks,
DC