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syntax: add Gleam language support #4045

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Merged
JoeKar merged 12 commits into from
Mar 28, 2026
+69 −0
Merged

syntax: add Gleam language support #4045

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e19c021
syntax: add Gleam language support
HiwarkhedePrasad Mar 15, 2026
992f30c
syntax: improve Gleam syntax highlighting
HiwarkhedePrasad Mar 15, 2026
aa2c965
Refactor Gleam syntax: fix overlaps, expand numbers/operators, add at…
HiwarkhedePrasad Mar 16, 2026
b6657ad
syntax: refine Gleam syntax with review fixes
HiwarkhedePrasad Mar 16, 2026
5f594d1
syntax: restore missing filetype field and remove comments
HiwarkhedePrasad Mar 16, 2026
c733704
syntax: improve tuple highlighting using region
HiwarkhedePrasad Mar 21, 2026
6357c79
syntax: fix indentation, add identifier rule, fix type ordering, expa…
HiwarkhedePrasad Mar 26, 2026
4367c87
add newline before micro judges me again
HiwarkhedePrasad Mar 28, 2026
3338524
style: fix indentation to 4 spaces
HiwarkhedePrasad Mar 28, 2026
fefa5d9
fix: remove trailing whitespace and add final newline
HiwarkhedePrasad Mar 28, 2026
da797ea
fix: ensure final newline at EOF
HiwarkhedePrasad Mar 28, 2026
0700b34
fix: remove extra newline at EOF
HiwarkhedePrasad Mar 28, 2026
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41 changes: 41 additions & 0 deletions runtime/syntax/gleam.yaml
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Original file line number Diff line number Diff line change
@@ -0,0 +1,41 @@
filetype: gleam

detect:
filename: "\\.gleam$"

rules:
# 1. Base Identifier Rule (Must be first so specific types below overwrite it)
- identifier: "\\b[A-Z][a-zA-Z0-9_]*\\b"

# 2. Built-in Types (Overwrites the identifier rule for these exact matches; Nil removed)
- type: "\\b(Int|Float|String|Bool|List|Option|Result|BitArray)\\b"

# 3. Constants (Nil safely kept here)
- constant: "\\b(True|False|Nil)\\b"

# 4. Keywords
- statement: "\\b(fn|let|case|if|use|import|pub|type|opaque|const|as|assert|panic|todo|echo)\\b"

# 5. Attributes / Decorators (Added for @external, @deprecated, etc.)
- preproc: "@[a-zA-Z0-9_]+"
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@Andriamanitra Andriamanitra Mar 16, 2026

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I think this is too permissive. I'm not sure if Gleam even has anything besides @external and @deprecated right now but if we follow vim's example we should only allow lowercase here: 1

Suggested change
- preproc: "@[a-zA-Z0-9_]+"
- preproc: "@[a-z][a-z_]*"

Footnotes

  1. https://github.com/vim/vim/blob/e21c4a649a830716599eadebad04ddf2393230bc/runtime/syntax/gleam.vim#L65 ↩


# 6. Operators (Moved to 'statement' for red highlighting; arithmetic, float math, and assignment added)
- statement: "(\\|>|->|<-|\\.\\.|<>|==|!=|<=|>=|&&|\\|\\||\\+\\.|-\\.|\\*\\.|/\\.|\\+|-|\\*|/|%|=|<|>)"

# 7. Numbers (Copied directly from Python's robust micro syntax as the maintainer requested)
- constant.number: "\\b0b[01]+\\b"
- constant.number: "\\b0o[0-7]+\\b"
- constant.number: "\\b0x[0-9a-fA-F]+\\b"
- constant.number: "\\b[0-9]+\\.[0-9]*([eE][+-]?[0-9]+)?\\b"
- constant.number: "\\b[0-9]+\\b"
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@Andriamanitra Andriamanitra Mar 16, 2026

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Contrary to what the comment claims these are not copied from Python, they're missing support for underscores.


# 8. Strings
- constant.string:
start: '"'
end: '"'
skip: "\\\\."

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@Andriamanitra Andriamanitra Mar 16, 2026

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Suggested change
skip: "\\\\."
skip: "\\\\."
rules:
- constant.specialChar: "\\\\."

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@HiwarkhedePrasad HiwarkhedePrasad Mar 16, 2026 •
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Hi @Andriamanitra, thanks again for the detailed feedback! I've made all the suggested changes:

  • Numbers now support underscores (e.g., 1_000_000)
  • Added float comparison operators (<., >., <=., >=.)
  • String escapes are now highlighted as special characters
  • Added tuple syntax #(...) highlighting
  • Attributes are now restricted to lowercase only

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# 9. Comments
- comment:
start: "//"
end: "$"