Introduce a "format String" Verb

[Miko4]

I like to suggest to introduce a verb for formating strings, similar to pythons %. I'd be a kind of inverse dollar.

I don't think there are many charters left that are available on most keyboards. On QWERTY keyboards the following charters are left: be §,€ or °. In the following I will use §, but that's just a example. /edit: I'd like to stress again: I'm not in favour of §, i just use that for the shake of the argument.

§ is diadic. The first argument is a string, the second one a array. Occurrence of "{}" in the left string are replaced by the value in the second argument, converted into a string

"A float: {} and the current time: {}" § (3.141; _t)

Is the same as

"A float: ",($3.141)," and the current time: ",($_t)

Formatting, equivalent to c could also be supported: (%d should be equivalent with {d}, %x equivalent to {x},

"A float: {2.3f} and the current time: {d}" § (3.141; _t)

would evaluate to

"A float: 03.141 and the current time: -616154346"

Of course Lists should be supported:

"A Pi and Tau: {1.3f}" § (3.141 6.283)

Kona code could functions could be embedded in doulbe curly braces:

"Several uneven numbers: {d{1+2*x}}" § (!100)

1+2*x is just regular kona code. That gets evaluted as a function for each element in the list. "d" is the format string.

I'd be happy to hear comments.

[bakul]

Not in favor of this. Too much magic for some typing convenience. K is minimal. This doesn't fit well in its model. Even kx.com's q (k4) doesn't provide such a verb. If you need it, you can write a function for it. Finally, kona is ascii only.

On Jun 23, 2015, at 7:24 AM, Miko4 [email protected] wrote:

I like to suggest to introduce a verb for formating strings, similar to pythons %. I'd be a kind of inverse dollar.

I don't think there are many charters left that are available on most keyboards. On QWERTY keyboards the following charters are left: be §,€ or °. In the following I will use §, but that's just a example

§ is diadic. The first argument is a string, the second one a array. Occurrence of "{}" in the left string are replaced by the value in the second argument, converted into a string

"A float: {} and the current time: {}" § (3.141; _t) Is the same as

"A float: ",($3.141)," and the current time: ",($_t) Formatting, equivalent to c could also be supported: (%d should be equivalent with {d}, %x equivalent to {x},

"A float: {2.3f} and the current time: {d}" § (3.141; _t) would evaluate to

"A float: 03.141 and the current time: -616154346" Of course Lists should be supported:

"A Pi and Tau: {1.3f}" § (3.141 6.283) Kona code could functions could be embedded in doulbe curly braces:

"Several uneven numbers: {d{1+2_x}}" § (!100) 1+2_x is just regular kona code. That gets evaluted as a function for each element in the list. "d" is the format string.

I'd be happy to hear comments.

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[kevinlawler]

Not in favor of this formulation, in favor of the general idea. I have always thought vprintf support, potentially as reserved verb _printf, was a good idea, provided it is trivial to implement and maintain. It is an almost universally supported language feature.

[bakul]

Better put! It'll be more like vprintf - the second arg will be a list. Don't expect it to be trivial! For some embedded code I once implemented it in C (from scratch but minus floats). Getting all the details right can be fiddly.

On Jun 23, 2015, at 7:48 AM, Kevin Lawler [email protected] wrote:

Not in favor of this formulation, in favor of the general idea. I have always thought vprintf support, potentially as reserved verb _printf, was a good idea, provided it is trivial to implement and maintain. It is an almost universally supported language feature.

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[JohnEarnest]

The §,€ and ° characters are not part of the US-QWERTY keyboard layout.

It would be possible to add some simple overloads to $ to get most of the desired functionality- you can already do things like

  ,/$("I have ";23;" coconuts")
"I have 23 coconuts"

When simple concatenation of the natural string conversion of types is acceptable, and gain more control by using prototypes and string lengths

  ,/("";2;"")$("foo ";65;" bar")
"foo 65 bar"

K4 does type conversion based on a left character argument and K5 does something along those lines with symbols. For example, in K5:

    `c`i`b$65 66 67
("A";66;1b)

There's still quite a bit of "unpopulated space" in left arguments to $.