Examples of Typecheckers

rascal-0.40.16

typepal-0.14.8

Synopsis

Examples of type checkers built with TypePal.

Description

TypePal is used in a new type checker for the Rascal meta-programming language and also in type checkers for over a dozen domain-specific languages created by http://swat.engineering in the domains finance, forensics and privacy.

To get you started more quickly, we give below a list of complete TypePal-based type checkers ranging from very simple (intended only to illustrate specific TypePal features) to type checkers for FeatherweightJava and the complete Pascal programming language. For each example we give a description, the most distinctive TypePal features that are used, and its source at GitHub. Each example has the same structure:

• Syntax.rsc the syntax of the example language.
• Checker.rsc the type checker for the language.
• Test.rsc functions to call the type checker and test framework.
• tests.ttl test cases for the type checker.
• examples (optionally) a directory with example.

Calc

What	The pocket calculator language Calc; we already covered it A simple pocket calculator language
Illustrates	fact, define, use, requireEqual, calculate, getType, report
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/calc

Pico

What	Toy language with declared variables in single scope, assignment, if and while statement
Illustrates	fact, define, use, enterScope, leaveScope, requireEqual, calculate, getType, report
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/pico

QL

What	A questionnaire language, for describing forms with text entry fields and computed values
Illustrates	fact, define, use, requireEqual, requireTrue, calculate, getType, report
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/ql

Fun

What	Functional language with explicit types, function declarations and calls, let and if expressions
Illustrates	fact, define, use, enterScope, leaveScope, requireEqual, calculate, getType, report
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/fun

ModFun

What	Extension of Fun with modules
Illustrates	PathRole, addPathToDef
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/modfun

Struct

What	Simple named records
Illustrates	useViaType, TypePalConfig, getTypeNamesAndRole
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/struct

Aliases

What	Struct, extended with type aliases
Illustrates	useViaType, TypePalConfig, getTypeNamesAndRole
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/aliases

StaticFields

What	Struct, extended with fields on non-record type
Illustrates	useViaType, TypePalConfig, getTypeNamesAndRole, getTypeInNamelessType
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/staticFields

StructParameters

What	Struct, with parameterized records
Illustrates	useViaType, TypePalConfig, getTypeNamesAndRole, getTypeInNamelessType, instantiateTypeParameters
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/structParameters

SmallOO

What	Small OO language without inheritance
Illustrates	useViaType, TypePalConfig, getTypeNamesAndRole
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/smallOO

FWJava

What	FeatherWeight Java, a minimal, Java-like, language with inheritance and constructors
Illustrates	useViaType, addPathToDef, isSubType, TypePalConfig, getTypeNamesAndRole, mayOverload, preSolver, setScopeInfo, getScopeInfo
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/fwjava

Pascal

What	The Pascal language (Second Edition, 1978)
Illustrates	useViaType, addPathToType, PathRole, isSubType, TypePalConfig, preCollectInitialization getTypeNamesAndRole
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/pascal

UntypedFun

What	Functional language with implicit (inferred) types, function declarations and calls, let and if expressions
Illustrates	fact, define, use, enterScope, leaveScope, requireEqual, calculate, getType, report, newTypeVar, calculateEager, requireUnify, unify
Source	https://github.com/cwi-swat/typepal/tree/master/src/examples/untypedFun