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Add syntax highlighting

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ajeffrey@roblox.com 2021-05-11 18:04:01 -05:00
parent 8206758bdc
commit 11f460d271
1 changed files with 9 additions and 9 deletions
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18
rfcs/generic-functions.md
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@ -20,19 +20,19 @@ is fine, but there is no way for a user to write the type of `id`.
Allow functions to take type parameters as well as function parameters, similar to Java/Typescript/... Allow functions to take type parameters as well as function parameters, similar to Java/Typescript/...
``` ```lua
function id<a>(x : a) : a return x end function id<a>(x : a) : a return x end
``` ```
Functions may also take generic type pack arguments for varargs, for instance: Functions may also take generic type pack arguments for varargs, for instance:
``` ```lua
function compose<a...>(... : a...) -> (a...) return ... end function compose<a...>(... : a...) -> (a...) return ... end
``` ```
This change is *not* only syntax, as explicit type parameters need to be part of the semantics of types. For example, we can define a generic identity function This change is *not* only syntax, as explicit type parameters need to be part of the semantics of types. For example, we can define a generic identity function
``` ```lua
local function id(x) return x end local function id(x) return x end
local x: string = id("hi") local x: string = id("hi")
local y: number = id(37) local y: number = id(37)
@ -41,7 +41,7 @@ type Id = typeof(id)
and two functions and two functions
``` ```lua
function f() function f()
return id return id
end end
@ -57,14 +57,14 @@ end
The types of these functions are The types of these functions are
``` ```lua
f : () -> <a>(a) -> a f : () -> <a>(a) -> a
g : <a>() -> (a) -> a g : <a>() -> (a) -> a
``` ```
so this is okay: so this is okay:
``` ```lua
local i: Id = f() local i: Id = f()
local x: string = i("hi") local x: string = i("hi")
local y: number = i(37) local y: number = i(37)
@ -72,7 +72,7 @@ so this is okay:
but this is not: but this is not:
``` ```lua
-- This assignment shouldn't typecheck! -- This assignment shouldn't typecheck!
local i: Id = g() local i: Id = g()
local x: string = i("hi") local x: string = i("hi")
@ -92,7 +92,7 @@ Types become more complex, so harder for programmers to reason about, and adding
Not having higher-kinded types stops some examples which are parameterized on container types, for example: Not having higher-kinded types stops some examples which are parameterized on container types, for example:
``` ```lua
function g<c>(f : <a>(a) -> c<a>) : <b>(b) -> c<c<b>> function g<c>(f : <a>(a) -> c<a>) : <b>(b) -> c<c<b>>
return function(x) return f(f(x)) end return function(x) return f(f(x)) end
end end
@ -100,7 +100,7 @@ Not having higher-kinded types stops some examples which are parameterized on co
Not having bounded types stops some examples like giving a type to the function that sums an non-empty array: Not having bounded types stops some examples like giving a type to the function that sums an non-empty array:
``` ```lua
function sum(xs) function sum(xs)
local result = x[0] local result = x[0]
for i=1,#xs for i=1,#xs