The Nineteenth Byte

9:00 PM

so a verb is an infix function, basically an operator. they can have right and left arguments, a single right argument, or no argument. The expression is parsed from left to right, so (if I implement some more ops) 3 + 4 * 6 = 3 + (4 * (6))

orlp

in what way are they different than regular operators?

Cᴏɴᴏʀ O'Bʀɪᴇɴ

when without arguments, they can do different stuff. so + * - is a new verb, and can be "called" by 5 (+ * -) 9. This would be different from 5 + * - 9, which would be parsed as 5 + (* - 9) with * - as unary operators

orlp

all right, that's kinda tricky

I think you need to be pretty precise in what is what, and what is allowed

also, there is no precedence?

Cᴏɴᴏʀ O'Bʀɪᴇɴ

nope

left to right

orlp

is there only infix and prefix?

or postfix as well?

(e.g. in Python, in "test"[5] the [5] is a postfix)

Cᴏɴᴏʀ O'Bʀɪᴇɴ

9:05 PM

oh, nope. that would be implemented as an operator, like 5 { "test" or something

only infix and prefix , yeah

Optimizer

9gag.com/gag/aq5MmMP

9gag.com/gag/adjAygQ

orlp

ok, I would start with marking the arity of verbs

integer = [0-9]+

nullary = integer

are there other verbs that do not take arguments?

Cᴏɴᴏʀ O'Bʀɪᴇɴ

I don't believe so, no.

orlp

unary = [-]

anything else?

Cᴏɴᴏʀ O'Bʀɪᴇɴ

I don't think so. Just clarifying: under this, each operator would have a fixed arity, right?

orlp

9:09 PM

not necessarily

Cᴏɴᴏʀ O'Bʀɪᴇɴ

okay, cool. ideally, most operators would have both unary and binary cases

orlp

can you compose verbs of different arities?

wait

5 + (* - 9) with * - as unary operators

you said there was nothing else

Cᴏɴᴏʀ O'Bʀɪᴇɴ

Well, yeah, it was an example.

I think - would suffice for unary for now

orlp

@CᴏɴᴏʀO'Bʀɪᴇɴ what is (- 9)?

would that be an expression?

Cᴏɴᴏʀ O'Bʀɪᴇɴ

yeah?

Nathan Merrill

9:14 PM

is there a convention for what $ does in languages?

I mean, in PHP, its used to start variables

but I can't think of any other language that uses it

orlp

@CᴏɴᴏʀO'Bʀɪᴇɴ does the thing that you're parsing always have to be a full expression?

quartata

@NathanMerrill Perl uses it

Nathan Merrill

for what?

orlp

e.g. + * wouldn't be a valid parse?

quartata

$ is a funny character (that's literally what they call them). It basically specifies the context in which the variable is accessed

$ is scalar context

orlp

9:15 PM

@NathanMerrill in formal languages it often denotes end of string

quartata

(i.e a number or a string, not a list)

Nathan Merrill

@orlp right, like regex

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@orlp It would be a valid parse.

Nathan Merrill

but as an operator?

quartata

@NathanMerrill It's XOR in Julia.

Cᴏɴᴏʀ O'Bʀɪᴇɴ

9:16 PM

@NathanMerrill In J, it gets the "shape" (dimensions) of an object

also it's "reshape"

orlp

@CᴏɴᴏʀO'Bʀɪᴇɴ then I'm missing information

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@orlp okay, yeah, gimme a sec

ohai

HAI! :D

:D

9:17 PM

sorry for being a bad influence

Nathan Merrill

hmmm, I think I'll make $ a unary operator then

Eᴀsᴛᴇʀʟʏ Iʀᴋ

Supposed to be writing essay about gaileo

@CᴏɴᴏʀO'Bʀɪᴇɴ I completely disagree. <3

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@EᴀsᴛᴇʀʟʏIʀᴋ :D

Eᴀsᴛᴇʀʟʏ Iʀᴋ

:D

quartata

@NathanMerrill What would it do?

Eᴀsᴛᴇʀʟʏ Iʀᴋ

9:18 PM

@CᴏɴᴏʀO'Bʀɪᴇɴ moving to skype

nothing

@EᴀsᴛᴇʀʟʏIʀᴋ kk

user definable :)

Oh, OK.

By the way you should have a way for overloading monadic and dyadic versions of an operator. I never understood why C++ didn't let you do that

Nathan Merrill

what do you mean?

Rainbolt

9:19 PM

Wow. I get way more work done when I am sick. I just look at all of the tasks thinking "Whyyyy won't you just be resolved already." and I punch them in the face with some code and move on to the next one.

quartata

public someObject operator+(someObject x) { ... }

public someObject operator+(someObject x, someObject y) { ... }

So you can do something with both +x and x+y for instance

Nathan Merrill

oh, I have a different solution to that

orlp

@quartata you can overload unary plus in c++

Nathan Merrill

well, operators are either unary or binary

orlp

@NathanMerrill or nullary, or ternary, or...

quartata

9:21 PM

@orlp Uh, you can? Oops.

Nathan Merrill

so +y is invalid code if x+y is valid

quartata

@NathanMerrill What about -y?

Nathan Merrill

hmm, good point

quartata

You could do _y like some languages I suppose, but ehhhhhhh

Nathan Merrill

it makes parsing harder, but -y is the negative() operator as opposed to "subtract"

mınxomaτ

9:22 PM

Nathan Merrill

but operators are always resolved by the variable on the right

quartata

@mınxomaτ I'm so confused right now

orlp

@quartata coliru.stacked-crooked.com/a/6ba623503c822c59

@mınxomaτ rainbowify it

quartata

@orlp fuck I'm stupid

thanks for showing me that

I had no idea

orlp

@quartata you can overload the dumbest things in C++

quartata

9:24 PM

@NathanMerrill What if you have string + int? Wouldn't that mean that it calls int's operator+()?

Nathan Merrill

yes

but that said, you can create adapters

Optimizer

@mınxomaτ chiat?

Nathan Merrill

adapt Int to Addable<String> {
    add(other) -> other.add(this)
}

quartata

@Optimizer ducat

Optimizer

oh ok

orlp

9:25 PM

@quartata coliru.stacked-crooked.com/a/8e26b755e81cf3cf

quartata

@orlp oh my

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@orlp Do you know anything about Jelly (how it works)?

quartata

that's just messed up

orlp

@CᴏɴᴏʀO'Bʀɪᴇɴ a tiny bit

Cᴏɴᴏʀ O'Bʀɪᴇɴ

J is a tiny bit like that

quartata

9:26 PM

@CᴏɴᴏʀO'Bʀɪᴇɴ By the way, Jelly doesn't have monadic/dyadic versions of verbs unlike J

Optimizer

so long and thanks for the fur.

img-9gag-fun.9cache.com/photo/aW6ynvZ_460sv.mp4

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@quartata yeah :|

quartata

@CᴏɴᴏʀO'Bʀɪᴇɴ orlp knows APL, explain it to him like that

Cᴏɴᴏʀ O'Bʀɪᴇɴ

OH

orlp

@quartata ?

no I don't

Cᴏɴᴏʀ O'Bʀɪᴇɴ

9:27 PM

darn

Nathan Merrill

hmmm, I don't think I'm going to allow -a

its a pretty rare use case

Cᴏɴᴏʀ O'Bʀɪᴇɴ

just use _

_a

Nathan Merrill

no, that's confusing

orlp

@CᴏɴᴏʀO'Bʀɪᴇɴ I just need to know

Nathan Merrill

it looks like another variable name

orlp

9:28 PM

what do you call the result of the parse?

quartata

@orlp I thought you said you did

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@orlp oh. a verb

quartata

@NathanMerrill Uhh, no it's not?

orlp

ah, so not an expression

allright, just to confirm

10 20 is not a valid verb

Cᴏɴᴏʀ O'Bʀɪᴇɴ

no

orlp

9:29 PM

* + is a valid verb

Cᴏɴᴏʀ O'Bʀɪᴇɴ

Yes.

Nathan Merrill

@quartata defining negative constants is pretty common, but simply doing something like a = -b isn't too common. In that case, you can simply do a = 0 - b

orlp

+ 10 is a valid verb

Cᴏɴᴏʀ O'Bʀɪᴇɴ

No, it's not

it's an expression, evaluating +'s unary form at 10

El'endia Starman

@NathanMerrill You will make programmers much happier if you allow a = -b.

orlp

9:30 PM

10 is a valid verb

Rainbolt

I 10 you

Nathan Merrill

@El'endiaStarman I know, but it makes for confusing situations

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@orlp It can be a niladic (no argument verb), or data

Nathan Merrill

if you do a - b what gets called?

Optimizer

Song that you are listening to right now. me:Pillowtalk

orlp

9:31 PM

@CᴏɴᴏʀO'Bʀɪᴇɴ so why is that a verb, but + 10 is not?

Nathan Merrill

hmmm, I guess that's not too bad

Rainbolt

@Optimizer Reckuhless behavyuuuuurrr

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@orlp uh. I guess 10 isn't a verb

El'endia Starman

@NathanMerrill I would think that binary minus has higher precedence than unary minus.

Optimizer

@Rainbolt yeahh

coz of that part only

and Gigi <3

El'endia Starman

9:32 PM

And/or you only do unary minus when there's no left argument.

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@Optimizer "Sweet dreams" by Eurythmics

Nathan Merrill

its actually not ambiguous, because a c is invalid

Rainbolt

beh duh daze, beh duh daze, bedduhdaze

Nathan Merrill

@El'endiaStarman right

orlp

@CᴏɴᴏʀO'Bʀɪᴇɴ so is a verb just a sequence of binary operators?

and nothing else?

Cᴏɴᴏʀ O'Bʀɪᴇɴ

9:32 PM

It's a sequence of operators.

(An operator is also a verb)

I'm now realizing how complicated what I want to do is ._.

orlp

so far that's really simple

El'endia Starman

One of my guiding principles in developing Pytek is essentially "If it's harder for the developer but easier for the user, it's worth doing." Of course, as a rule of thumb, there are exceptions, but I think it holds true in general.

orlp

I think you're just not describing it fully to me

quartata

@NathanMerrill Did a quick grep -r --include "*.java" -e "-[a-zA-Z]" on one of my projects and found quite a couple

especially in mathier parts

orlp

but there is nothing to parse here, except maybe parenthesis (although I don't know those interact)

Nathan Merrill

9:34 PM

@El'endiaStarman right, but I was trying to avoid the potential confusion to developers around operator overloading

Cᴏɴᴏʀ O'Bʀɪᴇɴ

So there are verbs, adverbs, and data. adverbs modify verbs, and they are parsed right-to-left. So say ~ is an adverb. 3 +~ 5 = 3 (+~) 5

Nathan Merrill

@quartata that could easily include statements like a-b

El'endia Starman

@NathanMerrill Ah-huh, I see.

quartata

@NathanMerrill I always have whitespace between my arguments like that

Cᴏɴᴏʀ O'Bʀɪᴇɴ

jsoftware.com/help/dictionary/partsofspeech.htm

Sorry, there are verbs, adverbs, conjunctions, and data. (and some others)

orlp

9:36 PM

verb = '(' verb ')' / binary verb?
binary = [-+*/]

that's what I have so far

a verb can be parenthesized

Optimizer

Jella Jella Jella Jella Jealous

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@orlp yes

orlp

or can be a binary operator, optionally followed by another verb

@CᴏɴᴏʀO'Bʀɪᴇɴ in what way does this not fulfill your problem?

it seems to simplistic to be the solution

Cᴏɴᴏʀ O'Bʀɪᴇɴ

I think it does

orlp

so which part didn't you tell me yet

Quill

9:39 PM

monring

orlp

are you sure you don't want to parse expressions?

rather than singular verbs?

Cᴏɴᴏʀ O'Bʀɪᴇɴ

alright, what's an expression? Just to be precise

orlp

that is my question to you

what are you parsing

Cyoce

Agh why did ruby have to make true and false two separate classes? ಥ_ಥ

Quill

@Optimizer Jelly_ous_

Cᴏɴᴏʀ O'Bʀɪᴇɴ

9:40 PM

@orlp I'm trying to make a language

orlp

@CᴏɴᴏʀO'Bʀɪᴇɴ unless that language only consists of verbs, I don't think we're done

you only described to me what verbs are

Cᴏɴᴏʀ O'Bʀɪᴇɴ

ok

orlp

but you also mentioned unary operators and numbers, which do not occur in the definition of a verb

Cᴏɴᴏʀ O'Bʀɪᴇɴ

"Verb" is a general class of operators -- unary or binary

Optimizer

firebug is officially merged into firefox

2

orlp

9:43 PM

@Optimizer firebug theme*

it seems

Optimizer

not just that

dom panel

also, the major maintainer of firebug: Honza is full time working on Firefox Devtools now

network logs in console too

orlp

verb = modified_verb+
modified_verb = primary_verb adverb?
primary_verb = '(' verb ') / binary
binary = [-+*/]
adverb = [~]

Eᴀsᴛᴇʀʟʏ Iʀᴋ

ohai

orlp

@CᴏɴᴏʀO'Bʀɪᴇɴ why are you so silent :(

Cᴏɴᴏʀ O'Bʀɪᴇɴ

sorry

hardcore multitasking

Eᴀsᴛᴇʀʟʏ Iʀᴋ

9:52 PM

rofl

Cᴏɴᴏʀ O'Bʀɪᴇɴ

kay sorry what was going on?

orlp

I added support for postfix adverbs

+~ or (+ *)~

Eᴀsᴛᴇʀʟʏ Iʀᴋ

shit wtf am I doing here

orlp

is that correct?

Eᴀsᴛᴇʀʟʏ Iʀᴋ

bai!

Cᴏɴᴏʀ O'Bʀɪᴇɴ

9:56 PM

@orlp it should work

orlp

ok, now that we can parse verbs

what do we do with that?

we still don't have numbers or expressions

Cᴏɴᴏʀ O'Bʀɪᴇɴ

alright, so expressions are combinations of numbers and verbs

(number) (verb) (number) (verb) ...

orlp

can expressions be parenthesized?

Cᴏɴᴏʀ O'Bʀɪᴇɴ

yes

orlp

e.g. (((5)) + 3) * 4

these are important details :)

Cᴏɴᴏʀ O'Bʀɪᴇɴ

9:57 PM

yeah

yeah, sorry XD

Nathan Merrill

ok, another language design question. when would the best name for a variable include a number?

I'm considering disallowing numbers in variable names :)

orlp

expr = primary (verb primary)*
primary = '(' expr ')' / number / unary primary
unary = [-]

verb = modified_verb+
modified_verb = primary_verb adverb?
primary_verb = '(' verb ') / binary
binary = [-+*/]
adverb = [~]

quartata

@NathanMerrill side1, side2, side3

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@orlp can there be two definitions of a rule?

quartata

Although I suppose you could always do side_one side_two side_three

Transcript for