.basDistinct files in the full Software Heritage archive (2026-06-04 export), dated by first appearance, following Desmazières, Di Cosmo, Lorentz (MSR 2025). Case-aggregated. citation.
Case variants in archive: .bas (730.2K), .BAS (72.4K), .Bas (1.4K), .BAs (5), .bAS (4), .bAs (2), .BaS (1), .baS (1) — aggregated above.
This extension is attributed to B4X; BASIC; FreeBASIC; QBasic; QuickBASIC; VBA; Visual Basic 6.0 as primary by 9 authoritative claims.
.bas among their extensions. Strength reflects whether the upstream source treated it as their primary extension.| Language | Source | Strength |
|---|---|---|
| B4X | linguist | primary |
| BASIC | linguist | primary |
| BASIC | pygments | primary |
| BASIC | wikidata | primary |
| FreeBASIC | wikidata | primary |
| QBasic | pygments | primary |
| QuickBASIC | linguist | primary |
| VBA | linguist | primary |
| Visual Basic 6.0 | linguist | primary |
| B4X | pygments | secondary |
| FreeBASIC | linguist | secondary |
| FreeBASIC | pygments | secondary |
| QuickBASIC | pygments | secondary |
| VBA | pygments | secondary |
| Visual Basic .NET | pygments | secondary |
| Visual Basic 6.0 | pygments | secondary |
| visual-basic | pygments | secondary |
| Liberty BASIC | wikipedia | proposed |
| SmallBASIC | wikipedia | proposed |
| Visual Basic .NET | wikipedia | proposed |
.bas on Wikidata
(property P1195) or in the Wikipedia infobox.
Source: data/derived/external_extension_index.csv.
Click Use as new PL on any row to open the
Add-PL form pre-filled with that entry's name, Wikipedia/Wikidata
URL, and this extension — one submission creates the PL + claim.
| Format | Class (Wikidata P31) | Suggested label | MIME | Notes | Action |
|---|---|---|---|---|---|
| FreeBASIC Q195929 compiled programming language | free software; programming language | — | — | — | Use as new PL ↗ |
| AmigaBASIC source Q105858496 file format | file format | — | application/octet-stream | — | Use as new PL ↗ |
| AmigaBASIC source (protected) Q105859238 file format | file format | — | application/octet-stream | — | Use as new PL ↗ |
.bas file actually is.| Rule | Predicts | Kind | Predicates (truncated) | Measured on SWH |
|---|---|---|---|---|
h/linguist/.bas/0 | B4X | predicates | [{"kind": "any", "regexes": ["\\A\\W{0,3}(?:.*(?:\\r?\\n|\\r)){0,9}B4(?:J|A|R|i)=true"]}] | |
h/linguist/.bas/1 | FreeBASIC | predicates | [{"kind": "any", "regexes": ["(?i)^[ \\t]*#(?:define|endif|endmacro|ifn?def|include|lang|macro|pragma)(?:$|\\s)", "(?i)^[ \\t]*dim( shared)? [a-z_][a-z0-9_]* as [a-z_][a-z0-9_]* ptr"]}] | |
h/linguist/.bas/2 | FreeBASIC | predicates | [{"kind": "any", "regexes": ["(?i)^[ \\t]*return "]}, {"kind": "not_any", "regexes": ["(?i)[ \\t]*gosub "]}] | |
h/linguist/.bas/3 | BASIC | predicates | [{"kind": "any", "regexes": ["\\A\\s*\\d"]}] | |
h/linguist/.bas/4 | QuickBASIC | predicates | [{"kind": "any", "regexes": ["^[ ]*(CONST|DIM|REDIM|DEFINT|PRINT|DECLARE (SUB|FUNCTION)|FUNCTION|SUB) ", "(#|$)lang:?\\s*\"?qb\"?", "(?i)'\\$INCLUDE:", "(?i)^[ ]*CLS[ ]*('|:|\\r|\\n)", "(?i)^[ ]*OPTIO | |
h/linguist/.bas/5 | VBA | predicates | [{"kind": "any", "regexes": ["\\b(?:VBA|[vV]ba)(?:\\b|[0-9A-Z_])", "^[ ]*(?:Public|Private)? Declare PtrSafe (?:Sub|Function)\\b", "^[ ]*#If Win64\\b", "^[ ]*(?:Dim|Const) [0-9a-zA-Z_]*[ ]*As Long(?:P | |
h/linguist/.bas/6 | Visual Basic 6.0 | predicates | [{"kind": "any", "regexes": ["^[ ]*Attribute VB_Name = "]}] |