Picotalk

Picotalk

Picotalk is a simple Smalltalk-like programming language and environment implemented in ECMAScript (JavaScript), mainly intended (but not limited) to teaching basic concepts of programming.

Project page at berliOS: https://developer.berlios.de/projects/picotalk/

Picotalk Isn't Smalltalk

Picotalk

Case is important: Picotalk distinguishes between identifiers starting with an uppercase letter and those starting with a lowercase letter. A beginning uppercase letter denotes a global name, e.g. a class name.
Brace array literals: Picotalk only supports the brace array notation for array literals.
Declaration of temporaries is a statement:

Data Structures

All data structures (AST, runtime objects) are now pure JSON data structures. This allows easier transport ove

AST Nodes

Each AST node is represented by a plain JavaScript object. The type of an AST node is determined by its type property. Legal values are the

Type	Properties
(all)	`loc`
Code
Script	`args`, `stmts`
Block	`args`, `stmts`
Method	`kind`, `selector`, `args`, `stmts`
Misc Statements
Temporaries	`temps`
Return	`expr`
Expressions
Assignment	`name`, `expr`
MessageSend	`kind`, `selector`, `receiver`, `args`
Name	`name`
GlobalName	`name`
Literal	`literal`
Self	-
Super	-
BraceArray	`exprs`
Primitive	`module`, `method`

Bytecode

Picotalk code is compiled to bytecode. In the current version the generated “bytecode” is just a simple JavaScript array.

Opcode	Parameters	Description
NOP	-	Does nothing
PUSH_NIL	-	Pushes the `nil` object onto the stack

History

Nov 2006: All AST node objects are now pure JSON data structures.