Luke Boswell (Jun 24 2025 at 10:22): Luke Boswell (Jun 24 2025 at 10:22):I've been down a rabbit hole on the API for our s-expressions... this is what I have so far.
(can_ir
(d_let :idx=#87
(p_assign (8:1-8:6) :ident="main!" :idx=#73)
(e_lambda (8:9-12:2) :idx=#86
(args
(p_underscore (8:10-8:11) :idx=#74))
(e_block (8:13-12:2)
(s_let (9:2-9:17)
(p_assign (9:2-9:7) :ident="world" :idx=#75)
(e_string (9:10-9:17) :idx=#77
(e_literal (9:11-9:16) :string="World")))
(e_call (11:2-11:31)
(e_lookup_external
(ext_decl (11:2-11:14) :qualified="pf.Stdout.line!" :module="pf.Stdout" :local="line!" :kind="value" :type_var=#79))
(e_string (11:15-11:30)
(e_literal (11:16-11:29) :string="Hello, world!"))))))
(s_import (6:1-6:17) :module="pf.Stdout" :idx=#72
(exposes)))
I'm trying to make it easier to read and clearer by adding attributes :name=value to nodes instead of just hardcore nesting
Luke Boswell (Jun 24 2025 at 10:24):Doing this simplifies the rule for newlines, basically one for each child
Anthony Bullard (Jun 24 2025 at 10:27):why is :ident="main!" better than (ident "main!")?
Anthony Bullard (Jun 24 2025 at 10:32):It would seem that the newline rule should be a newline for each child node, and all attribute nodes are first and on the same line as the tag for the sexpr
(tag (line:col-line:col) (attr1 val) (attr2 val) ...
(child_1_tag (line:col-line:col) (attr1 val) ...
(child_2_tag) ...
...)
It would seem that the newline rule should be a newline for each child node, and all attribute nodes are first and on the same line as the tag for the sexpr
This was the key change... I'll give the formatting a go with parens again
Anthony Bullard (Jun 24 2025 at 10:33):I would probably go full sexpr and have no custom microformats to parse
(tag (line col line col) (attr1 val) (attr2 val) ...
(child_1_tag (line col line col) (attr1 val) ...
(child_2_tag) ...
...)
(can_ir
(d_let (idx #87)
(p_assign (8:1-8:6) (ident "main!") (idx #73))
(e_lambda (8:9-12:2) (idx #86)
(args
(p_underscore (8:10-8:11) (idx #74)))
(e_block (8:13-12:2)
(s_let (9:2-9:17)
(p_assign (9:2-9:7) (ident "world") (idx #75))
(e_string (9:10-9:17) (idx #77)
(e_literal (9:11-9:16) (string "World"))))
(e_call (11:2-11:31)
(e_lookup_external
(ext_decl (11:2-11:14) (qualified "pf.Stdout.line!") (module "pf.Stdout") (local "line!") (kind "value") (type_var #79)))
(e_string (11:15-11:30)
(e_literal (11:16-11:29) (string "Hello, world!")))))))
(s_import (6:1-6:17) (module "pf.Stdout") (idx #72)
(exposes)))
ok, i don't think the # is necessary
Luke Boswell (Jun 24 2025 at 10:35):(can_ir
(d_let (id 87)
(p_assign (8 1 8 6) (ident "main!") (id 73))
(e_lambda (8 9 12 2) (id 86)
(args
(p_underscore (8 10 8 11) (id 74)))
(e_block (8 13 12 2)
(s_let (9 2 9 17)
(p_assign (9 2 9 7) (ident "world") (id 75))
(e_string (9 10 9 17) (id 77)
(e_literal (9 11 9 16) (string "World"))))
(e_call (11 2 11 31)
(e_lookup_external
(ext_decl (11 2 11 14) (qualified "pf.Stdout.line!") (module "pf.Stdout") (local "line!") (kind "value") (type_var 79)))
(e_string (11 15 11 30)
(e_literal (11 16 11 29) (string "Hello, world!")))))))
(s_import (6 1 6 17) (module "pf.Stdout") (id 72)
(exposes)))
10 messages were moved here from #compiler development > casual conversation by Luke Boswell.
Anthony Bullard (Jun 24 2025 at 10:37):Maybe tag the Pos node and put the line/col pairs in ()s? Like (pos (6 1) (6 17))?
Luke Boswell (Jun 24 2025 at 10:37):It's an improvement over the current I think https://github.com/roc-lang/roc/blob/main/src/snapshots/hello_world_with_block.md#canonicalize
Anthony Bullard (Jun 24 2025 at 10:37):Definitely
Anthony Bullard (Jun 24 2025 at 10:39):you want to do the least amount of parsing possible, while it still being readable to someone unfamiliar with the specific format (but who has a base level of understanding of sexpr)
Luke Boswell (Jun 24 2025 at 10:39):I'm thinking something custom for Region's is unnavoidable
Anthony Bullard (Jun 24 2025 at 10:39):are we saving the ids so that we can recover the IR from the Sexpr representation?
Luke Boswell (Jun 24 2025 at 10:40):I got a bit carried away there. Only some nodes (patterns I think?) need to show them.
Luke Boswell (Jun 24 2025 at 10:40):Other nodes reference them by NodeIdx. Also TypeVars are NodeIdx's
Luke Boswell (Jun 24 2025 at 10:41):I figure any node that is referenced (or could be) by another probably should show it's id
Anthony Bullard (Jun 24 2025 at 10:41):I'm just trying to understand if that's useful for debugging
Luke Boswell (Jun 24 2025 at 10:41):I don't know though... just experimenting with it
Luke Boswell (Jun 24 2025 at 10:42):I guess we use the Region info to map back to the source, and the type information will reference a pattern in a declaration maybe.
Anthony Bullard (Jun 24 2025 at 10:42):Ok, as far as region you can just have it be a standard s-expr symbol if you start with @
Luke Boswell (Jun 24 2025 at 10:43):How?
Anthony Bullard (Jun 24 2025 at 10:43):@6!1-6!17 is a valid S-expr symbol
Anthony Bullard (Jun 24 2025 at 10:44):And that can just be an atom
Anthony Bullard (Jun 24 2025 at 10:45):I think @ is helpful for understanding that it's a region (or related to where it's "at")
Luke Boswell (Jun 24 2025 at 10:45):(can_ir
(d_let (id 87)
(p_assign @8!1-8!6 (ident "main!") (id 73))
(e_lambda @8!9-12!2 (id 86)
(args
(p_underscore @8!10-8!11 (id 74)))
(e_block @8!13-12!2
(s_let @9!2-9!17
(p_assign @9!2-9!7 (ident "world") (id 75))
(e_string @9!10-9!17 (id 77)
(e_literal @9!11-9!16 (string "World"))))
(e_call @11!2-11!31
(e_lookup_external
(ext_decl @11!2-11!14 (qualified "pf.Stdout.line!") (module "pf.Stdout") (local "line!") (kind "value") (type_var 79)))
(e_string @11!15-11!30
(e_literal @11!16-11!29 (string "Hello, world!")))))))
(s_import @6!1-6!17 (module "pf.Stdout") (id 72)
(exposes)))
But unfortunately : is not usually valid there
Anthony Bullard (Jun 24 2025 at 10:46):Hmm. I'm surprised with the syntax highlighting
Anthony Bullard (Jun 24 2025 at 10:46):Maybe (@ (8 1) (8 16)) is better?
Luke Boswell (Jun 24 2025 at 10:47):Yeah I'm trying to find something nice
Luke Boswell (Jun 24 2025 at 10:47):What about this?
(p_assign @8-1-8-6 (ident "main!") (id 73))
I think that's my favourite so far.
Anthony Bullard (Jun 24 2025 at 10:52):That looks fine to me
(p_assign @8-1-8-6 (ident "main!") (id 73))
Just the smallest of comments here, but canonically, sexpr symbols should be in kebab case, not snake
Anthony Bullard (Jun 24 2025 at 10:53):but if we are using the string value of a zig tag directly, it might not be worth a conversion
Luke Boswell (Jun 24 2025 at 10:56):I might do a pass through each s-expr node and change that as I go.
Anthony Bullard (Jun 24 2025 at 11:02):up to you, just calling it out
Anthony Bullard (Jun 24 2025 at 11:02):you've been doing a great job with these and the snapshots!
Luke Boswell (Jun 24 2025 at 11:10):Here's an updated PARSE section
(app @1-1-3-57
(provides @2-3-2-10
(exposed-lower-ident (text "main!")))
(record-field @3-28-3-55 (name "pf")
(e-string @3-41-3-54
(e-string-part @3-42-3-53 (raw "../main.roc"))))
(packages @3-2-3-57
(record-field @3-4-3-27 (name "somePkg")
(e-string @3-13-3-26
(e-string-part @3-14-3-25 (raw "../main.roc"))))
(record-field @3-28-3-55 (name "pf")
(e-string @3-41-3-54
(e-string-part @3-42-3-53 (raw "../main.roc"))))))
The kebab makes is more searchable using ctrl-F
Anthony Bullard (Jun 24 2025 at 11:13):I think this looks great
Luke Boswell (Jun 24 2025 at 11:23):And this is the app we started with, Can section
(can-ir
(d-let (id 87)
(p-assign @8-1-8-6 (ident "main!") (id 73))
(e-lambda @8-9-12-2 (id 86)
(args
(p-underscore @8-10-8-11 (id 74)))
(e-block @8-13-12-2
(s-let @9-2-9-17
(p-assign @9-2-9-7 (ident "world") (id 75))
(e-string @9-10-9-17 (id 77)
(e-literal @9-11-9-16 (string "World"))))
(e-call @11-2-11-31
(e-lookup-external
(ext-decl @11-2-11-14 (qualified "pf.Stdout.line!") (module "pf.Stdout") (local "line!") (kind "value") (type-var 79)))
(e-string @11-15-11-30
(e-literal @11-16-11-29 (string "Hello, world!")))))))
(s-import @6-1-6-17 (module "pf.Stdout") (id 72)
(exposes)))
Beautiful
Luke Boswell (Jun 24 2025 at 11:36):Random side question... does anyone know how to rename a file so git is happy. I change the casing on this but I'm not sure git has carried it through.
Screenshot 2025-06-24 at 21.35.33.png
Kiryl Dziamura (Jun 24 2025 at 11:38):maybe this would help
https://adamj.eu/tech/2022/12/09/git-change-case-of-filenames/
tldr: git mv
Luke Boswell (Jun 24 2025 at 11:40):Thank you.
Joshua Warner (Jun 24 2025 at 15:29):FWIW I think greppability of the s-expr names (i.e. exact match between what a thing is called in the s-expr and what it's called in the zig source) is really useful for ramping up in an unfamiliar codebase. Agree it's a bit more readable with kebab-case, but that does give me a bit of pause...
Last updated: Jul 06 2025 at 12:14 UTC