pseudocode-i18n

Current version: 0.9.1. License: GNU GPL-3.0-or-later.

pseudocode-i18n lets students, teachers and developers write the same pseudocode language in several natural languages, while keeping one common semantic model underneath.

Write a normal .pseudo or .algo file, in French, Spanish, Italian, Portuguese, German, Dutch, Danish, Swedish, Norwegian, Finnish, Greek, Ukrainian, Russian or English. The language can be detected automatically. The same source can then be checked, semantically linted, formatted, executed, transpiled bidirectionally with Python, or exported/rendered as a Mermaid flowchart/algorigram.

# language: fr

age est un entier
age = 17

Si age >= 18 Alors:
    Afficher "Majeur"
Sinon:
    Afficher "Mineur"
Fin

Transpiles to:

age: int
age = 17

if age >= 18:
    print("Majeur")
else:
    print("Mineur")

Why this project?

Pseudocode used in classrooms is rarely standardized. The same ideas are written as Afficher, Écrire, Mostrar, Escribir, Print, Display, Si ... Alors, If ... Then, FinSi, Fin, or with indentation only.

pseudocode-i18n deliberately accepts these common teaching variants, maps them to one AST, and provides one predictable canonical formatter.

Main goals:

• two equivalent source extensions for every language: .pseudo and .algo;
• automatic language detection with an explicit override when needed;
• tolerant input, but deterministic canonical formatting;
• indentation-based block semantics, like Python;
• optional FinSi / FinPour / FinFonction-style terminators for constructs that need a separate closer;
• a generic optional terminator (Fin, Fim, Fine, Ende, End);
• localized types, constants, operators, input/output verbs and control flow;
• bidirectional Python transpilation for the supported subset, without losing useful type information;
• a shared language definition for CLI, Pygments, MkDocs and VS Code integrations.

0.9.1 — consolidated language, diagnostics, runtime and editor contract

Version 0.9.1 is the coordinated documentation-and-consolidation release for the complete 0.9 language line. It keeps the same language direction as 0.9.0 while documenting and locking the features added during the 0.9 development cycle:

• 14 data-driven languages with Unicode identifiers, automatic detection, # language: xx / # lang: xx, project configuration and localized infinitive/imperative synonyms;
• strict contracts for explicitly annotated variables, parameters, attributes and returns: for example, declaring i: chaîne / i: string and later assigning an integer is a type error, while unannotated variables remain intentionally dynamic for progressive teaching;
• typed operation checking based on the Pseudocode type model rather than Python implementation accidents: incompatible arithmetic/concatenation is diagnosed statically, while intentional Python-like operations such as string/list repetition by an integer remain supported;
• a recovering multi-diagnostic linter that reports independent problems across the whole file instead of hiding later errors behind the first malformed line;
• precise diagnostics for incomplete compound syntax (for example a counted repeat missing its localized “times” word), incomplete input statements, undefined/unassigned/unused symbols, arity/return/control-flow problems, invalid operations, type mismatches and OOP visibility/override errors;
• localized learner-facing syntax/runtime errors with the original Pseudocode line number and source line. Python remains the execution backend but normal error messages do not expose Python exception class names;
• a performance-oriented source-map design: comment-only mapping metadata is generated during transpilation and localization work happens only on the exceptional path, so normal execution has no per-statement tracing cost;
• math and random as explicit standard modules plus local project Pseudocode modules (.pseudo / .algo), token-level unknown-module/member diagnostics and a localized local override when a local module collides with a standard name;
• natural localized import orders such as importe sqrt depuis math en tant que rac, while keeping infinitive and imperative import verbs equivalent in every language;
• universal alea() → real in [0, 1[ and entalea(a, b) → integer in inclusive [a, b], in addition to existing localized random helpers;
• universal English public, private and protected accepted in every language in addition to each language's localized spellings;
• an editor-neutral semantic index, snippets, exhaustive localized syntax help and runtime/error catalogues shared by the LSP, VS Code, Thonny and future editor integrations;
• bidirectional Pseudocode ↔ Python transpilation, canonical formatting, Mermaid/SVG/PNG flowcharts and execution tracing remain part of the same core API.

The core remains deliberately efficient: editor intelligence and richer diagnostics must not add overhead to normal Pseudocode execution.

0.9 language-server, editor-help and runtime foundations

Version 0.9 adds an editor-neutral semantic index with exact source ranges, definitions, references, signatures and symbol metadata. The shared pseudocode-i18n-languageserver consumes this API to provide diagnostics, snippets plus semantic completion, pedagogical hover help, signature help, document symbols, navigation, rename and formatting without duplicating the language grammar. VS Code and Thonny both consume this same intelligence.

The core also owns the editor-help catalogue and localized runtime-error catalogue so future IDEs receive the same explanations. Editor help is fully localized (for example Syntaxe in French and Sintaxis in Spanish) and deliberately lists every accepted spelling for a construct, including imperative/infinitive synonyms and automatically accepted accentless variants. Runtime error mapping is designed for execution performance: generated Python contains comment-only source markers, normal execution has no per-statement tracing overhead, and source-line localization is performed only when an exception occurs. Syntax and runtime failures are rendered in the Pseudocode language with the original Pseudocode line number and source line; Python backend exception class names are not exposed in the normal learner-facing message.

Object-oriented access modifiers are language-neutral concepts. Every one of the 14 languages accepts its localized spellings and the universal English spellings public, private and protected; accentless variants supplied by the language packs remain accepted as well.

The 0.9 linter also recovers after independent malformed lines instead of stopping at the first one. A counted loop missing its localized “times” word, an incomplete input statement and a bad module name can therefore all receive squiggles in the same document. Known-bad lines are neutralized only inside the static-analysis pass; the user's source is never rewritten and invalid code is never made executable.

Imports are now resolved through a deliberately small Pseudocode module model. math and random are standard modules; sibling/project .algo and .pseudo files are local Pseudocode modules. Arbitrary Python packages are not exposed implicitly. Standard module names keep priority, while the localized local keyword explicitly forces a same-named local module. For example in French:

importe sqrt depuis math en tant que rac
importer sqrt depuis math en tant que rac
importe geometrie
importe aire depuis geometrie
importe aire depuis local geometrie en tant que aire_locale

Unknown modules (PSE113) and unknown imported members (PSE114) are reported on the offending token. Local modules are transpiled only when imported and cached afterwards, so this support adds no per-statement execution overhead.

Two universal pedagogical random helpers are available in all 14 languages, alongside the existing localized aliases:

alea()          -> real in [0, 1[
entalea(a, b)   -> integer in [a, b] (both bounds included)

In French, the existing hasard(n) remains the integer helper for [0, n[, and aleatoire(a, b) remains an alias of the inclusive integer range helper.

0.8 Unicode and 14-language expansion

Version 0.8 expands the data-driven language registry from 6 to 14 languages: French, Spanish, Italian, Portuguese, German, Dutch, Danish, Swedish, Norwegian, Finnish, Greek, Ukrainian, Russian and English. Identifiers are Unicode-aware across parsing, semantic analysis and highlighting, so Greek and Cyrillic variable/function names are first-class identifiers.

Automatic detection is exercised against all bundled language examples, while # language: xx remains the explicit override for short or deliberately ambiguous snippets. The Usage documentation is now generated as a complete per-language tree with real variables, conditions, loops, functions, classes, tools, flowcharts and exhaustive vocabulary tables.

0.7 typed signatures, object model and data-driven languages

Version 0.7 turns the semantic foundations into a structured teaching-language model while keeping all annotations optional.

Classe Personne:
    private nom: chaîne
    protected age: entier

    Constructeur(nom: chaîne, age: entier):
        this.nom = nom
        self.age = age
    Fin

    public Fonction anniversaire() -> entier:
        self.age = self.age + 1
        Renvoyer self.age
    Fin
Fin

The 0.7 core adds:

• untyped, partially typed and fully typed function/method parameters and return values;
• structured class bases, typed members and native instance/class/function types;
• localized constructors (Constructeur, Constructor, Costruttore, Construtor, Konstruktor, Constructor);
• strict self == this semantics for the current instance;
• single/multiple inheritance, inherited-member resolution, super, override, static/class methods and native public / protected / private checks;
• stronger semantic checks for annotated calls/returns, inheritance, overrides and member access;
• a fully data-driven language registry: the core discovers languages/*.yml, while Pygments, MkDocs and VS Code regenerate their language-facing artifacts from that shared data.

Python remains the execution backend; it does not define the Pseudocode type system or access-control semantics.

0.6 native type system, linter and structured diagnostics

Version 0.6 adds a language-native semantic layer without making Python the definition of Pseudocode semantics. The existing Python transpiler remains the execution backend used by pseudo file.pseudo; linting is a separate static-analysis capability.

The core now provides:

• an internal type system (integer, float, string, boolean, collections, functions/classes/modules, null, void, unknown and any);
• native expression analysis over a Pseudocode expression AST, rather than Python's ast;
• NullType semantics for localized null literals such as French Vide (which still transpiles to Python None for execution);
• symbol/scope tracking and type inference for assignments, collections, calls, indexing and common operators;
• semantic diagnostics for undefined or unassigned variables, unused variables, wrong argument counts, unreachable statements, incompatible declared/actual types, invalid operations and control-flow misuse;
• structured diagnostics with stable codes, severity, source ranges and optional expected/actual types;
• diagnostics localized to the language resolved from the .pseudo file;
• a tolerant line-local preflight pass for incomplete compound statements and invalid type annotations, so editors underline the actual faulty line instead of a downstream indentation consequence;
• multiple independent line-local syntax/type errors can be reported in one lint pass;
• structural keywords remain part of the highlighting vocabulary even while their statement is incomplete; syntax validity is communicated by diagnostics/squiggles rather than by removing keyword highlighting;
• a new pseudo lint file.pseudo command with text, JSON and JSONL output.

For example:

pseudo lint exercice.pseudo
pseudo lint exercice.pseudo --format json

Running remains unchanged:

pseudo exercice.pseudo

A file is not required to pass the linter before execution. This deliberate separation keeps the teaching runtime compatible while allowing editors and CI to consume richer static diagnostics.

For example, an incomplete counted repetition is diagnosed on its own line:

Répéter 5:
    Afficher "bonjour"

The French diagnostic points to line 1 and proposes Répéter … fois; it does not blame the indented Afficher line. Likewise, x: produit is reported as an unknown type (PSE112) when French is active. IDE clients receive the same localized ranges and messages through the language server.

0.5 language and visualization foundations

Version 0.5 includes a larger Python-like teaching surface while keeping one multilingual AST:

• explicit algorithm boundaries (Début ... Fin and translated long/named forms);
• processes and subprocesses;
• no-fall-through Selon / Cas / Autrement (switch/case) in all supported languages;
• ÉcrireSansSaut and EffacerÉcran families;
• Python-like //, %, **, slices and negative indices, plus pedagogical ^, <>, localized logical/MOD words;
• project-wide index_base: 0|1, applied coherently to strings, lists, tuples, slices and substring helpers;
• localized imports with aliases in both traditional and natural word orders (De math Importer sqrt En tant que rac and Importe sqrt depuis math en tant que rac) plus universal Python import/from/as;
• localized math/string/conversion/random helpers plus universal Python spellings such as sqrt(), abs(), len(), pow(), log() and pi;
• named flowchart symbols and execution-aware flowchart highlighting;
• pseudo trace JSON/JSONL execution traces for synchronized source/flowchart/variable visualizers.

The VS Code integration consumes these core capabilities for a live flowchart and step-by-step execution view; editor integrations do not reimplement language semantics.

Install

python -m pip install pseudocode-i18n

On a system-managed Python installation where you deliberately use system packages:

python -m pip install --break-system-packages pseudocode-i18n

The package installs two equivalent commands:

pseudo
pseudocode

Two equivalent source extensions, automatic language detection

Every pseudocode source file uses either of the two canonical extensions, regardless of language:

algo.pseudo
algo.algo

.pseudo and .algo are strictly equivalent; neither extension carries language information.

In the normal case, the language is detected from the source:

pseudo algo.pseudo

If detection needs to be overridden, put a universal metadata directive at the beginning of the file:

# language: es

or force it from the CLI:

pseudo --lang es algo.pseudo

Resolution order is:

CLI/API > # language: xx > project configuration > automatic detection > fallback

The canonical form is # language: fr. The aliases # language fr, # lang: fr and # lang fr are also accepted; language and lang are synonyms and the colon is optional. # is the only comment/directive marker; // is integer division.

Pseudocode in several languages

The bundled language order is French, Spanish, Italian, Portuguese, German, Dutch, Danish, Swedish, Norwegian, Finnish, Greek, Ukrainian, Russian, then English. Every Usage topic is generated separately for all 14 languages.

Français

Si note >= 10 Alors:
    Afficher "Admis"
Sinon:
    Afficher "Ajourné"
Fin

Español

Si nota >= 10 Entonces:
    Mostrar "Aprobado"
Sino:
    Mostrar "No aprobado"
Fin

Italiano

Se voto >= 10 Allora:
    Mostra "Promosso"
Altrimenti:
    Mostra "Non promosso"
Fine

Português

Se nota >= 10 Então:
    Mostrar "Aprovado"
Senão:
    Mostrar "Reprovado"
Fim

Deutsch

Wenn note >= 10 Dann:
    Ausgeben "Bestanden"
Sonst:
    Ausgeben "Nicht bestanden"
Ende

English

If grade >= 10 Then:
    Display "Passed"
Else:
    Display "Failed"
End

Flexible conditionals, canonical formatting

French conditionals accept, among others:

Si condition:
Si condition
Si condition Alors:
Si condition Alors

Sinon, Sinon Si, optional Alors, optional colons, specific terminators and generic Fin are also accepted.

For example, all these tolerant variants converge with pseudo format toward:

Si condition Alors:
    Afficher "oui"
Sinon Si autre_condition Alors:
    Afficher "peut-être"
Sinon:
    Afficher "non"
Fin

Indentation determines the actual block structure. End markers are always optional.

Input and output synonyms

Vocabulary is language data rather than parser code.

French examples:

Afficher "Bonjour"
Écrire "Bonjour"
Ecrire "Bonjour"

Saisir n
Lire n
Lis "Ton nom", nom

A prompt-only input statement such as Lis "Allo" is incomplete because the entered value has nowhere to be stored. The linter reports this before execution and points to the original source line.

Spanish examples:

Mostrar "Hola"
Escribir "Hola"

Leer n
Introducir n
Lee "Tu nombre", nombre

Natural localized imports are accepted in the same data-driven way. For example:

Importe sqrt depuis math en tant que rac
Importa sqrt desde math como raiz

Both transpile to a Python from ... import ... as ... statement. Matching is case-insensitive, and accentless equivalents of declared accented spellings are generated automatically.

Variables and optional types

Type declarations are never mandatory. You can write ordinary Python-like assignments:

a = 2
a = a + 2

or add pedagogical type declarations. The compact name: type notation is accepted in every source language as well as the localized natural forms:

i: chaîne
a est un entier
a, b sont des flottants
nom est une chaîne
notes est un tableau
d est un dictionnaire
vus est un ensemble
coordonnees est un tuple

An explicit annotation is a contract: after i: chaîne, assigning i = 0 is a localized PSE105 type error. Binary operations are also checked when both operand types are known. Numeric arithmetic is allowed between numeric types, strings/lists/tuples concatenate only with compatible families, and string/list repetition by an integer remains valid (3 * "ha"), while combinations such as 3 + " pommes" or Vrai + 1 are rejected. Untyped variables remain gradual/dynamic; add an annotation when a stable pedagogical type is required.

They are preserved in Python as annotations:

a: int
a: float
b: float
nom: str
notes: list
d: dict
vus: set
coordonnees: tuple

Bundled semantic type families:

The same model is localized in all 14 bundled languages.

Vide / null values are not empty collections

A localized null constant has the same semantic role as Python None:

x = Vide

becomes:

x = None

Spanish accepts Vacío and its automatically generated accentless form Vacio; the other languages provide their own localized vocabulary.

This is distinct from empty collections:

[]              # empty list
{}              # empty dictionary, exactly like Python
Ensemble()      # empty set -> set()
Tuple()         # empty tuple -> tuple()
Dictionnaire()  # empty dictionary -> dict()

Assignment forms

All of these are accepted as assignments:

a = 2
a := 2
a <- 2
a ← 2
2 -> a
2 → a

The canonical formatter emits =.

Membership and mathematical notation

Localized word operators and mathematical symbols are equivalent.

French examples:

x Dans E
x Inclus Dans E
x ∈ E

x Pas Dans E
x Non Dans E
x Non Inclus Dans E
x ∉ E

They transpile to Python in / not in.

Repeat loops

Repeat a fixed number of times:

Répéter 5 fois:
    Afficher "Bonjour"
Fin

All 14 bundled languages accept the infinitive and the natural second-person imperative for action verbs whenever those forms are distinct, not only for repeat. For example, French accepts Afficher / Affiche, Lire / Lis, Retourner / Retourne, Importer / Importe and Répéter / Répète; Spanish accepts Importar / Importa; German accepts Importieren / Importiere and natural multi-word imperatives such as Ausgeben / Gib aus. Languages where both grammatical forms have the same spelling naturally expose only that spelling. Localized collection methods follow the same principle where a verb has distinct forms.

becomes:

for _ in range(5):
    print("Bonjour")

Post-test repeat-until loop:

n = 0
Répéter:
    n = n + 1
Jusqu'à ce que n >= 5

Jusqu'à n >= 5 is equivalent. The Jusqu'à ... line closes the post-test loop, so no Fin follows it.

becomes:

n = 0
while True:
    n = n + 1
    if n >= 5:
        break

The body therefore executes at least once.

Fast direct execution

pseudo file.pseudo still transpiles to Python, but the CLI executes the generated Python inside its own short-lived process instead of starting a second Python interpreter. Language definitions and compiled grammar templates are cached per process, and the C-backed safe YAML loader is used when available. These changes reduce startup overhead substantially for the tiny programs used in introductory teaching while keeping Python strictly as the execution backend.

Run, check, transpile and format

Run directly:

pseudo programme.pseudo

Check syntax:

pseudo check programme.pseudo

Transpile pseudocode → Python:

pseudo transpile programme.pseudo -o programme.py
pseudo transpile -i programme.pseudo -o programme.py
pseudo transpile -input programme.pseudo -output programme.py

Transpile Python → pseudocode:

pseudo transpile programme.py -o programme.pseudo --lang fr
pseudo transpile -i programme.py -o programme.pseudo --lang fr
pseudo transpile -input programme.py -output programme.pseudo --lang fr

The direction is inferred from .pseudo/.algo versus .py. Unsupported Python statements fail explicitly rather than being approximated silently.

Canonical formatting in place:

pseudo format programme.pseudo
pseudo format programme.pseudo --check

Flowchart / algorigram export and rendering

Export Mermaid source:

pseudo flowchart programme.pseudo -o programme.mmd

Render directly to SVG or PNG:

pseudo render programme.pseudo -o programme.svg
pseudo render programme.pseudo -o programme.png
pseudo render programme.mmd -o programme.svg
pseudo render programme.mmd -o programme.png

pseudo svg is an SVG-only alias. Rendering uses Mermaid CLI, auto-detects Chromium/Chrome when possible, and uses a transparent background by default.

Python API

Automatic language resolution is the default:

from pseudocode_i18n import (
    SUPPORTED_EXTENSIONS, detect_language, format_pseudocode, parse,
    render_mermaid, resolve_snippets, snippets_for_language,
    to_mermaid, transpile, transpile_python,
)

source = '''
Si x > 0 Alors:
    Afficher x
Fin
'''

detection = detect_language(source)
tree = parse(source)
python_source = transpile(source)
canonical_source = format_pseudocode(source)
mermaid = to_mermaid(source)
pseudo_again = transpile_python(python_source, language="fr")
render_mermaid(mermaid, "programme.svg")

assert SUPPORTED_EXTENSIONS == (".pseudo", ".algo")
french_snippets = snippets_for_language("fr")
resolved_snippets = resolve_snippets(source, fallback="fr")

Force a language when needed:

python_source = transpile(source, language="fr")

detect_language() returns the selected ISO 639-1 code together with confidence/scores through a LanguageDetection object. snippets_for_language() exposes the canonical localized editor/LSP snippets, while resolve_snippets() applies the same language precedence as normal source processing.

Project configuration and custom synonyms

Canonical project file:

pseudocode.config.yml

Example:

language: auto
fallback_language: fr
index_base: 0

format:
  colons: true
  indent: 4
  end_markers: true

render:
  browser: auto
  background: transparent
  mermaid_cli: auto

languages:
  fr:
    keywords:
      display:
        add:
          - Montrer

lang: is a supported alias for the project-level language: key. The canonical spelling in documentation remains language::

lang: es
fallback_language: fr

This makes Montrer an additional French display synonym without modifying the parser.

Bundled language data live in:

pseudocode_i18n/languages/fr.yml
pseudocode_i18n/languages/es.yml
pseudocode_i18n/languages/it.yml
pseudocode_i18n/languages/pt.yml
pseudocode_i18n/languages/de.yml
pseudocode_i18n/languages/nl.yml
pseudocode_i18n/languages/da.yml
pseudocode_i18n/languages/sv.yml
pseudocode_i18n/languages/no.yml
pseudocode_i18n/languages/fi.yml
pseudocode_i18n/languages/el.yml
pseudocode_i18n/languages/uk.yml
pseudocode_i18n/languages/ru.yml
pseudocode_i18n/languages/en.yml

They define vocabulary, patterns, end forms, type names, method/function aliases and flowchart labels. This is the preferred place for language-specific evolution.

Add another language

Languages use ISO 639-1 two-letter codes.

For example:

yarn generate nl

creates a Dutch language scaffold containing the full vocabulary, diagnostics, editor text and Usage-documentation contract, then regenerates documentation. Fill the translations and choose language.order, then run the same command again to validate/regenerate it. No parser, linter, lexer, MkDocs or VS Code source registry needs to be edited.

Development

Bootstrap:

corepack enable
yarn setup

Run tests:

yarn test

Run the documentation locally:

yarn dev

LAN/mobile documentation server:

yarn dev:lan

Full validation before committing/releasing:

yarn bfc

yarn bfc synchronizes the project version from package.json, validates version consistency, lints, runs tests, regenerates/checks/builds the documentation, and builds the Python package.

Version source of truth

package.json is the single source of truth for the project version.

yarn version:sync

synchronizes derived Python metadata and the version displayed in this README. MkDocs narrative pages can use:

__PSEUDOCODE_I18N_VERSION__

and site/hooks/version.py replaces that placeholder from package.json during the documentation build.

Documentation policy

Documentation is part of every change. Grammar, CLI, configuration, formatting, transpilation, flowcharts, language data, highlighting vocabulary and development workflow changes must update their corresponding documentation in the same revision.

The MkDocs home page is generated from this README, so the repository landing page and documentation landing page cannot silently drift apart.

License

GNU General Public License version 3 or later (GPL-3.0-or-later). See LICENSE.

AUTRES PROJETS de ce développeur

The Pseudocode ecosystem is split into small reusable projects so that each integration can share the same grammar instead of reimplementing it:

• pygments-lexer-pseudocode-i18n — Pygments lexer using the common multilingual semantic vocabulary and Python-like token categories.
• mkdocs-pseudocode-i18n — MkDocs integration for pseudocode in teaching/documentation sites.
• vscode-pseudocode-i18n — editor integration for .pseudo/.algo files, formatting and language-aware authoring.

The core project is pseudocode-i18n and its documentation is published at rod2ik.gitlab.io/pseudocode-i18n.