Pseudo takes an algorithm / a simple program and generates idiomatic code for it in Python, JavaScript, C#, Go and Ruby.
Pseudo achieves that with translation on two layers: it uses the target language syntax and it can express standard library methods/api of language X using language Y's native standard library
Sorry: I lied, remaking the git history in a way that it appears most of the work is after 1 march: I was finishing my work in a company in february and I wanted to hide the fact i've worked on pseudo in that time: I actually started more active work somewhere around 20-th february if I remember correctly, somewhere around the second half of february. I am not sure if i have that original git history anymore: sorry to Clevertech(the company)/any observers, this was a really ugly thing to do.
Pseudo consumes "Pseudo AST" which corresponds to a very clear, statically typed and somehow limited subset of a language:
basic types and collections and standard library methods for them
integer, float, string, boolean
lists
dicts
sets
tuples/structs(fixed length heterogeneous lists)
fixed size arrays
regular expressions
functions with normal parameters (no default/keyword/vararg parameters)
classes
exception-based error handling with support for custom exceptions (target languages support return-based error handling too)
I/O: print/input, file read/write, command arg handling, system and subprocess commands
iteration (for-in-range / for-each / iterating over several collections / while)
conditionals (if / else if / else)
standard math/logical operations
a lot more in future
Those constructs and entities have almost the same behavior and very same-spirited api in a lot of the languages which Pseudo would support.
Each example contains a detailed README and working translations to Python, JS, Ruby, Go and C#, generated by Pseudo
a football results processing command line tool
a verbal expressions-like library ported to all the target languages
PSEUDO AST:
NORMAL CODE PSEUDO STANDARD LIBRARY INVOCATIONS
|| ||
|| ||
|| API TRANSLATOR
|| ||
|| ||
|| \/
|| IDIOMATIC TARGET LANGUAGE
|| STANDARD LIBRARY INVOCATIONS
|| ||
\/ \/
STANDARD OR LANGUAGE-SPECIFIC MIDDLEWARES
e.g.
name camel_case/snake_case middleware
convert-tuples-to-classes middleware
convert-exception-based errors handling
to return-based error handling middleware
etc
||
||
||
||
TARGET LANGUAGE CODE GENERATOR
defined with a dsl aware
that handles formatting
automatically
||
||
||
\/
Python / C# / Go / JS / Rubypip install pseudo #only python 3 supported
# probably you'd like to try the python-to-pseudo-to-js/go/etc compiler
pip install pseudo-pythonyou can directly generate pseudo ast from Python using Pseudo-Python
pseudo-python a.py # generates a.pseudo.yamland then translate the ast
pseudo a.pseudo.yaml go # or ruby / js / csharp / py / cppor you can directly translate from python to another language
pseudo-python a.py b.rb # or c.cspseudo.generate(pseudo_ast, language) # pseudo_ast is a plain dict or a pseudo Node-based treepseudo.generate_from_yaml(pseudo_ast, language) # pseudo_ast is yaml-encoded pseudo astFor quick experiments it's easier to use generate_main
from pseudo import * # ok for a repl
print(generate_main([
assignment(
local('a', 'Int'),
call(local('g'), [to_node(0), to_node('')], 'Int'))], 'rb'))
a = g(0, '')In the future Pseudo can add a lisp-like dsl for fast manual creation of ast nodes, but currently it's more useful for its main goal: consuming automatically generated pseudo ast and then transpiling it to the target languages.
Supporting full-blown Ruby to Python/Javascript to C++ auto translation is hard.
However often we need to just express an algorithm, a self-contained core of a library, a simple command line tool and the act of manual porting to another languages feels somehow .. primitive.
Often that code is(or can be) expressed in very similar way, with
similar constructs and basic types and data structures. On that level a lot of languages are very similar and the only real difference is syntax and methods api. That's a feasible task for automatic translation and actually the existance of pseudo is to fullfill the needs of several other existing projects/ideas.
Another powerful thing about Pseudo is its standard library. It can accumulate a serious number of methods/idioms and it can act like e.g. a truly cross-platform, target-language-aware equivalent of lodash
Pseudo is still young (it's basically less than two weeks old), but it already has a base on which it can improve really quickly (adding support for another language is basically just a matter of 3-4 hours currently)
Using pseudo's DSL it's easy to add support for a new language, so it's feasible to expect support for most popular languages and even different versions of them (e.g. EcmaScript 6/7, Perl 5/6 Java 7 / 8)
Currently pseudo-python is usable, and there are plans for pseudo-ruby or pseudo-js
The AST format uses basic data structures available in most languages. The nodes correspond to
dictionaries with type key corresponding to the node type and field_name keys corresponding to
the node fields, similar to the widely popular estree ecmascript format.
Pseudo can consume ast either serialized in .pseudo.yaml files or directly as
dictionary objects through it's pseudo.generate(ast, output_lang) API
The implementation goal is to make the definitions of new supported languages really clear and simple.
If you dive in, you'll find out a lot of the code/api transformations are defined using a declarative dsl with rare ocassions of edge case handling helpers.
That has a lot of advantages:
Less bugs: the core transformation code is really generalized, it's reused as a dsl and its results are well tested
Easy to comprehend: it almost looks like a config file
Easy to add support for other languages: I was planning to support just python and c# in the initial version but it is so easy to add support for a language similar to the current supported ones, that I added support for 4 more.
Easy to test: there is a simple test dsl too which helps all language tests to share input examples like that
However language translation is related to a lot of details and a lot of little gotchas, tuning and refining some of them took days. Pseudo uses different abstractions to streamline the process and to reuse logic across languages.
PSEUDO AST:
NORMAL CODE PSEUDO STANDARD LIBRARY INVOCATIONS
|| ||
|| ||
|| API TRANSLATOR
|| ||
|| ||
|| \/
|| IDIOMATIC TARGET LANGUAGE
|| STANDARD LIBRARY INVOCATIONS
|| ||
\/ \/
STANDARD OR LANGUAGE-SPECIFIC MIDDLEWARES
e.g.
name camel_case/snake_case middleware
convert-tuples-to-classes middleware
convert-exception-based errors handling
to return-based error handling middleware
etc
||
||
||
||
TARGET LANGUAGE CODE GENERATOR
defined with a dsl aware
that handles formatting
automatically
||
||
||
\/
OUTPUTPseudo has undergone some changes through the last year in my local repo, the new release somewhere in the next months should contain some of this roadmap.
They might seem comparable at a first glance, but they have completely different goals.
Pseudo wants to generate readable code, ideally something that looks like a human wrote it/ported it
Pseudo doesn't use a target language runtime, it uses the target language standard library for everything (except for JS, but even there is uses lodash which is pretty popular and standard)
Pseudo's goal is to help with automated translation for cases like algorithm generation, parser generation, refactoring, porting codebases etc. The fact that you can write compilers targetting Pseudo and receiver translation to many languages for free is just a happy accident
well.
pseudo(code)
Copyright © 2015 2016 Alexander Ivanov
Distributed under the MIT License.