First version of Pinn, in ANTLR and Go. Archived, but works as is.

Pinn is a computer language that lets you be correct.

Pinn is a statically typed, imperative language for computers.

• Syntax taken mostly from Go.
• Carefully chosen ideas from Swift.

Specification

Lexical

Most lexical elements are borrowed from Go. Later elements include support for _ in numeric literals and binary floating point.

Element Types

• int. Always a signed 64-bit.
• bool. Standard, true or false.
• string. Immutable.
• big. Big integer.
• float. Big float. See Go.
• char. Character. Implemented as UTF-32.

Group Types

• Scalar is a single element.
• map. Key is always a string. Like Go, a missing string returns the zero value.
• slice. Pointer to a region of an array or slice. Shares memory in Go and copies in Swift.
• array. Arrays are passed by value.

Expressions

• Almost all taken from Go, so much like c/Java. Conditional expression was put back in.

Compilation unit

• ( <function> | <statement>)+ EOF

block

• "{" { <statement> } "}"

statement

• while <expr> <block>
  • Evaluate expr. If true, execute block and repeat this line. If false, go on.
• repeat <block> while <expr>
  • Execute block. Evaluate expr. If true, repeat this line.
• return [<expr>] ;
  • Return from function. The expr must match the return type, or empty if there is none. If global, there is no return type.
• if <expr> <statement> [else <statement>]
  • Evaluate expr. If true, exectue first statement. If false, either move on or execute second statement.
• guard <expr> else <block>
  • Evaluate expr. If false, execute block. The block must relinquish control, with a return, break, or continue.

Variable declaration

• <id> <kind> [ = <expr_list> ]
  • Declare id of kind type. Optionally initialize it.
• id := <expr>
  • Short declaration.

The grammar is clean of implementation language and is written in ANTLR. It has implementations in Go and Swift. The Swift implementation is more recent and at https://github.com/keppel2/pinnSwift.

Running Go version

Get ANTLR from https://www.antlr.org/download.html.

Save the following to hello.pinn:

func main ( ) { print ("Hello, world."); }

Then run the ANTLR code and run go run . -f hello.pinn. You should see:

Hello, world.

Running ANTLR

• java -jar <path_to_antlr_jar> -Dlanguage=Go -o pparser Pinn.g4

Elements

Notation

|  alternation
()  grouping
[]  option (0 or 1 times)
{}  repetition (0 to n times)
literal  type as specified
<production>  rule specified elsewhere
"{" "[" ...  notation elements as literals