Language grammar

[dr-orlovsky]

A top-level structure of the contractum file consists of sections in form of

FILE = [SECTION]+
SECTION = SECTION_KEYWORD IDENT (SECTION_PARAM IDENT,*)+ SECTION_CONTENT?

Keywords for sections are:

• use imports
  • data type library written in Strict encoding (either *.sten source code or compiled schema *.ses with symbol file *.sem)
  • Contractum library (either as a *.con source file or a compiled contractum library *.conlib)
  • AluVM library, at the present moment only as *.ald compiled library
• types defines new data types
• schema defines new schema
• subschema defines new subschema
• interface defines new interface
• implement provides an implementation of interface for a schema
• contract defines new contract genesis
• transition defines new state transition
• extension defines new state extension
• application defines application-level code for the schema

Each section content consists of a list of declarations, each of which starts with a newline and may occupy multiple lines. Each declatation has the following form:

SECTION_CONTENT = DECLARATION*
DECLARATION = TERM IDENT? "::" (ARG_DECL "->")? ARG_DECL "\n" DECLARATION_CONTENT

Thus, declaration consists of:

• Declaration term; the list of possible terms is specific for each section
• Input arg declaration, which may be omitted. If the input arg declaration is omitted it is replaced with the declaration-specific default argument declaration, which is Seal for the owned declaration in the schema section and () for all other sections
• Output arg declaration, which can't be omitted

Argument declaration lists one or more arguments consisting of variable name and type name separated with non-line-breaking whitespace; the variable name can be omitted if the variable is not used in the declaration content.

Argument type name must be a valid strict encoding data type, or other declaration ident introduced in the same section.

Examples:

schema Name            -- this is section declaration with `Name` used as section identifier
  owned SomeType :: U8  -- this is equivalent to
  owned SomeType :: _ Seal -> _ U8
  
  genesis :: SomeType -- this is equivalent to
  genesis _ :: () -> _ SomeType

  op OpName :: input SomeType -> output SomeType

Reserved words (keywords) include section names and all declaration terms for all sections.

Case conventions:

• All keywords are lowercase single-word (schema etc);
• All type names and term identifier names are capitalized (SomeName) with abbreviations written in caps (RGBName);
• All variable names are snake-cased (someVariable)