Cathy

A simple programming langauge.

Features currently implemented

• User defined functions (through let binding)
• User defined variables
• Control structures - while, if-then-else
• Lists
• Integer arithmetic
• Real arithmetic
• Operator precedence
• Associativity of operators
• Parenthesization of expressions

Ideas for future

• Polymorphism
• Subtyping
• Universal types
• Exception handling system
• General recursion
• New datatypes - tuples, sums, variants, records
• Syntactic sugar to implement for structure
• Hexadecimal arithmetic
• Case structure
• Bit manipulation

Installation

To install cathy, first install gcc, flex and bison. Most Linux distributions come with these installed. If yours doesn't, use the package manager to install them.

On Arch Linux,

sudo pacman -S gcc flex bison

Next clone (or download as a .zip file using button above) the repository.

git clone https://github.com/iambrj/cathy
cd cathy

Install and run cathy

make
make clean # to remove temporary files generated
./cathy

Syntax

Identifiers for varible begin with an alphabet (lowercase or uppercase). Values for variables can be assigned using = operator.

> a = 3
 =    3
> b = 4
 =    4
> a + b
 =    7

if-then-else block works as follows

> if a > b then a; else b;
 =    4

Note the use of ; to end then and else

Functions can be defined using let. Example

> let square(a) = a * a;
Defined square

Note that function declarations must be terminated by a ;