Dialect

Inspired by Felienne Hermans and her multi-lingual programming language Hedy.

Why does one need to learn English to program? Dialect adds localized aliases for Julia keywords for fun and educational purposes. Standard Julia spellings remain valid. Currently implements Nederlands and Deutsch. Contributions are welcome!

using Dialect
nederlands()

functie som(n)
    totaal = 0
    voor i in 1:n
        totaal += i
    einde
    terug totaal
einde

deutsch() enables German aliases. The equivalent language-code calls are enable(:nl) and enable(:de); locale names such as enable("nl_NL.UTF-8") work too. active_dialect() returns the active locale code, and disable() removes the aliases and restores the original parser.

Dialect requires Julia 1.13 or newer, because it installs a parser through Core._setparser!.

Automatic selection

Loading Dialect opts in to automatic selection:

using Dialect

At load time, it checks for LocalPreferences.toml.

[Dialect]
locale = "nl"

Preferences are loaded through Preferences.jl, so they can also be inherited from environments higher in the load path. They can be set programmatically before restarting Julia:

using Dialect, Preferences
set_preferences!(Dialect, "locale" => "nl")

The preference is read once and enables that locale for the process. A locale suffix on a filename takes precedence for that file, whether or not a global locale is configured:

include("algorithm.nl.jl")
include("algorithm.de.jl")

Filename-based parsing temporarily changes Julia's global keyword table under a lock, then restores the configured global locale. Explicit nederlands(), deutsch(), or a local preference determines the default for the REPL and files without a locale suffix, and also lets REPL syntax highlighting see the localized keywords.

Limitations

Dialect currently extends the private Base.JuliaSyntax.Tokenize._kw_hash table and installs a parser through the private Core._setparser! API. These internals may change between Julia versions. Explicitly enabled aliases also modify a process-global keyword table; filename-based parsing serializes its temporary changes with a lock.

JuliaSyntax's keyword hash was designed for ASCII keywords of at most ten characters. Non-ASCII aliases can appear to work, but the hash does not distinguish different non-ASCII characters in the same position. For example, enabling German makes für a for token, but also incorrectly makes får, főr, and fЖr for tokens. Unicode aliases are therefore not safe with the current approach, even though the German locale currently ships a few (für, während, rückgabe).

Not every entry in JuliaSyntax's keyword list is a structural keyword. In particular, isa is a word operator whose source spelling is retained during conversion to an expression: x iseen T becomes a call to iseen, not isa(x, T). Dialect therefore exports iseen(x, T) and istein(x, T), which simply forward to isa, so the aliases behave as expected.

Aliases naming a keyword kind that the running Julia version does not know are silently skipped, which keeps locale files portable across versions. In Julia 1.13 this drops the Dutch typegroep, ganaar, and VERSIE.

Conversion to Expr also discards localized spellings for structural keywords: a function written with functie displays as function. The original spelling remains available only in source-backed JuliaSyntax trees.

Related

LocalizedLiterals.jl provides string literals (fr"Hello World") that are used to automatically translate via Google Translate.