https://github.com/dankolesnikov/simplelanguage

Programming language - Scala subset
https://github.com/dankolesnikov/simplelanguage

interpreters parsing scala

Last synced: 1 day ago
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Programming language - Scala subset

• Host: GitHub
• URL: https://github.com/dankolesnikov/simplelanguage
• Owner: dankolesnikov
• Created: 2018-04-09T03:49:36.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2018-04-09T10:24:19.000Z (over 6 years ago)
• Last Synced: 2024-12-14T07:30:22.995Z (20 days ago)
• Topics: interpreters, parsing, scala
• Language: Scala
• Homepage:
• Size: 2.93 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Simple Language

> Programming language interpreter, similar to Scala subset

## Description

A programming language interpreter developed in a Programming Paradigms class with Professor Cay Horstmann at SJSU.

Simple Language is similar to Scala subset but differs in several ways:

* Only two types: integer and functions

* Defs end with semicolons

* Block has a single expression

* Function literals have syntax `{ ident, ident, ... => block }`

* `if` fakes `Boolean` similar to C: > 0 is true, <= 0 is false

## Grammar

	block ::= (valdef | fundef)* expr

	expr ::= expr2 | "if" "(" expr ")" block "else" block

	expr2 ::= term (( "+" | "-" ) term)*

	term ::= factor (( "*" | "/" ) factor)*

	factor ::= wholeNumber | "(" expr ")" | ident | funcall | funliteral

	funcall ::= ident "(" (expr ("," expr)*)? ")"

	funliteral ::= "{" (ident ("," ident)*)? "=>" block "}"

	valdef ::= "val" ident "=" expr ";"

	fundef ::= "def" ident "=" funliteral ";" 

## Examples 

Simple addition and multiplication

	val a = 1;

	val b = 6;

	a * a + b * b

	

Function literal

	val max = { x, y => if (x - y) x else y };

Higher-order function

	val twoTimes = { f, x => f(f(x)) }; 

	twoTimes({x => x * x}, 2)

	

Recursion

	def fac = { x => if (x) x * fac(x - 1) else 1 };

**Curry**

Multiplication

	val multiply = { x => { y => x * y } } ;

	multiply(3)(4)

Lists:

	val list = 1 :: 2 :: Nil;

	val y = isEmpty(list);

	val x = head(1 :: Nil);

### Credits

[Cay Horstmann](http://horstmann.com/), SJSU