make from an operator

[metagn]

Just extra syntax (for DSLs and macros) to use. I don't see any downsides to this.

There are other keywords that work fine when made operators, but may be limited to infix only. for, if, else, when, while with precedence 1 can be used for list comprehensions (though you have to do a if b for c in d unlike python) or postfix conditionals, and using is just an English word that sounds normal when used as a using b.

[Araq]

Needs an update of the manual and a changelog entry.

[metagn]

Docs CI failures seem to stem from b8e6ea7

[timotheecour]

out of curiosity, what are use cases for from as an operator?
as noted in nim-lang/RFCs#84 (comment), from is already usable in UFCS/MCS, eg: str.from "12"

The situation with math operators such as and is different because and returns a value so can be pipelined, eg a and b or c, whereas the use cases I have in mind for from (void return type, as in nim-lang/RFCs#84 (comment)) by definition can't be pipelined since they return void:

var ret: string
ret.from "12" # returns void

it may be confusing if operators returns void or non-void depending on the overload.

[metagn]

1. Manual proposes it for a future syntax in Nim itself
2. Syntax flexibility for DSLs, I'm having trouble thinking of examples but from is too natural a word to not be able to use in freeform. I wanted to add more keywords that have uses in DSLs/macros (let odds = x if x mod 2 == 0 for x in @[1'u8, 2, 3, 4, 5] using newSeq, check OP these are compatible with current Nim) but those would be too much at a time, so I thought from was an acceptable start

[timotheecour]

both 1 and 2 are good enough reasons, thanks! (and I'd be forever grateful if you could turn alias into a keyword :-) )