kasuboski/gleam-code-corpus

Gleam Code Corpus

A structured, attributed corpus of 22,581 Gleam source files collected from 1,528 GitHub repositories for continued pre-training and code generation research.

Overview

This dataset contains .gleam source files from the Gleam programming language ecosystem. Every file includes full attribution — repo owner, name, URL, license, star count, and Hex.pm package metadata where available.

What this is for:

• Continued pre-training (CPT) of code-focused language models
• Fine-tuning models for Gleam code generation
• Research on small programming language ecosystems
• Reference corpus for Gleam idioms and patterns

What this is NOT:

• Instruction/response pairs (see the companion gleam-sft dataset, coming later)
• Documentation (language tour, hexdocs — separate dataset, coming later)
• Raw/unfiltered data (generated files, unlicensed code, and duplicates have been removed)

Dataset Configs

Config	Files	Size	Description
all	22,581	27 MB	Full filtered corpus
official	296	422 KB	Official repos only (gleam-lang, gleam-wisp, lustre-labs)
community_top	6,702	8 MB	Community repos with stars ≥ 10 or Hex downloads ≥ 1,000

All configs contain only permissively licensed, deduplicated code.

Schema

Each record is a single .gleam file with full attribution:

Field	Type	Description
id	string	{owner}/{repo}/{file_path} — unique identifier
source	string	Always "github"
code	string	Raw file contents
file_path	string	Path within the repository
repo_url	string	GitHub repository URL
repo_owner	string	Repository owner/organization
repo_name	string	Repository name
repo_description	string	Repository description from GitHub
stars	int	GitHub star count at collection time
is_official	bool	True if owner is gleam-lang, gleam-wisp, or lustre-labs
license	string	Normalized SPDX license identifier
license_raw	string	Original license string from source
authors	list[string]	Repository authors/contributors
hex_package	string?	Hex.pm package name (null if not on Hex)
hex_downloads	int?	Hex.pm download count (null if not on Hex)
fork	bool	Whether the repo is a fork (unreliable — see notes)
archived	bool	Whether the repo is archived
collected_at	string	ISO 8601 timestamp of collection
commit_sha	string	Git commit SHA of the snapshot
schema_version	int	Schema version (currently 1)

Collection Methodology

1. Discovery: GitHub search API with language:gleam, using star-range + date-range chunking to bypass the 1,000-result-per-query limit. Discovered 4,660 unique repositories across 17 query chunks.

2. Enrichment: Cross-referenced with Hex.pm search=gleam (1,035 packages) to add package names and download counts.

3. Collection: Shallow-cloned each repo (git clone --depth 1), extracted all .gleam files. 4,489 repos processed, 0 clone failures.

4. Filtering: Applied a multi-stage quality pipeline:

   Filter	Removed	Reason
   Generated files (>50K chars)	666	Auto-generated schemas, lookup tables, data dumps
   Stub files (<20 chars)	316	Empty/placeholder files
   Unlicensed repos	42,368	No license and no Hex package
   Non-permissive licenses	0	GPL, AGPL removed
   Exercism repos	840	Same exercises solved repeatedly — low diversity
   Content deduplication	2,642	Identical code from different repos (kept highest-starred)

   69,413 raw files → 22,581 clean files (67% reduction)

Statistics

Corpus

• 22,581 files from 1,528 repos
• 4.3M lines, 121M characters
• Median file: 2,692 chars; Mean: 5,352 chars; Max: 49,945 chars

License Distribution

• MIT: 57% (13,068 files)
• Apache-2.0: 40% (8,723 files)
• Other permissive: 3% (MPL-2.0, BSD, ISC, Unlicense, 0BSD, CC0-1.0)

Source Distribution

• src/ files: 48%
• test/ files: 24%
• examples/ files: 6%
• Other: 22%

Star Distribution

Stars	Files	%
0	6,904	31%
1–4	6,842	30%
5–9	3,432	15%
10–49	3,602	16%
50–99	757	3.4%
100–999	918	4.1%
1000+	126	0.6%

Known Limitations

• fork field is unreliable: GitHub search API doesn't consistently mark forks. All records show fork=false. Some near-duplicate fork content may be present (content dedup catches exact copies only).
• Near-duplicate forks: Diverged forks (e.g., Ivan-Vakhula07/lustre vs lustre-labs/lustre) survived dedup because their files differ slightly. These are valid Gleam code and not harmful for training.
• Semi-generated content: dusty-phillips/monks_of_style contributes 496 files (2.2%) of auto-generated CSS property wrappers from MDN documentation. Each file is valid Gleam but follows an identical template.
• Hex.pm enrichment incomplete: Only 44% of files (10,015) have Hex package metadata. The rest are from repos not published on Hex.
• Collection snapshot: Data was collected on 2026-05-28. Repositories may have changed since.

Licensing

This dataset aggregates code from many repositories, each with their own license. The license field in each record contains the normalized SPDX identifier. All included code is under permissive licenses:

• MIT
• Apache-2.0
• MPL-2.0
• BSD-3-Clause
• BSD-2-Clause
• ISC
• Unlicense
• 0BSD
• CC0-1.0

The dataset card and curation scripts are released under the same license terms as the underlying code. See individual records for specific license attribution.

How to Use

from datasets import load_dataset

# Load full corpus
ds = load_dataset("kasuboski/gleam-code-corpus", config="all")

# Load only official Gleam repos
ds = load_dataset("kasuboski/gleam-code-corpus", config="official")

# Load community top (stars >= 10 or hex_downloads >= 1000)
ds = load_dataset("kasuboski/gleam-code-corpus", config="community_top")

# Access a record
record = ds["train"][0]
print(record["code"])           # the Gleam source code
print(record["repo_url"])       # GitHub URL for attribution
print(record["license"])        # SPDX license identifier

Acknowledgments

• The Gleam language team and community
• Hex.pm for package metadata
• All the repository authors whose code is included in this corpus