Lexical rules

1.1 Identifiers#

carbon
IDENTIFIER      = [a-z_][a-zA-Z0-9_]*       // variables, fields, flow names
TYPE_IDENTIFIER = [A-Z][a-zA-Z0-9_]*         // types, enums, Core names
CORE_URI        = "core://" PATH             // Core-to-Core addressing
PLUGIN_URI      = IDENTIFIER "://" PATH      // Plugin addressing

1.2 Literals#

Literal	Syntax	Examples
String	`"..."`	`"hello world"`
Multi-line string	`"""..."""`	`"""multi\nline"""`
Integer	`-?[0-9]+`	`42`, `-7`, `1_000_000`
Float	`-?[0-9]+\.[0-9]+`	`3.14`, `-0.5`
Boolean	`true \| false`	`true`
Null	`null`	`null`
Duration	`INTEGER UNIT`	`30s`, `5m`, `1h`, `7d`, `2w`
Date	`YYYY-MM-DD`	`2026-01-15`
DateTime	ISO 8601	`2026-01-15T10:30:00Z`
Money	`FLOAT` with money type	`1500.00` (type provides currency)
Semver	`"MAJOR.MINOR.PATCH"`	`"1.2.3"`

1.3 Comments#

scaicore
// Single-line comment

/* Multi-line
   comment */

1.4 Keywords (Reserved)#

Active in v0.1:

scaicore
@core @flow @transformer @evaluator @pipeline @types @test
@plugin_interface @core_interface @config @debug @budget
@rigid @guarded @flexible @parallel @foreach @match @while
@checkpoint @core_call @await_responses @try @mock
@conversation_policy @plugins @memory @llm @models @constraints
@reference @triggers @webhook @schedule @api @on @internal
@param @hot_reload @runtime_configurable @secret @model_call
@given @when @then @property
if else match return yield break continue emit
true false null
import from as pub type enum async instance

Reserved for future versions:

tsql
@adaptive @recipe @stream @cache @version goto