6.21 Static and Dynamic Lookup

8.12

6.21 Static and Dynamic Lookup🔗ℹ

expression

#%dynamism

Initially indicates dynamic mode, but intended to be redefined by or use_dynamic.

This binding is not exported by rhombus/static, and a binding to indicate static mode is exported, instead.

definition

use_static

(Re-)defines #%dynamism to require certain static information and consistency with static information:

A static . accesses a component of a target only when the access can be resolved statically, otherwise the . form is a syntax error.
A static #%index looks up a value only when the lookup operator can be specialized statically (e.g., to a list or map lookup), otherwise the lookup form is an error.
A static ++ works only when the append operation can be specialized statically (e.g., to a list or map append), otherwise the operator use is an error.
A static #%call does not require static information about functions and methods for calls, but it reports an error when the number of supplied arguments is inconsistent with static information that is available for the called function or method. Similarly, := assignment to a property is rejected if static information does not declare the property as supporting assignment.
A static with requires static information for a class on the left-hand side of with (i.e., the object to be functionally updated). An error is reported if a field name supplied on the right-hand side of with does not correspond to the field of the class.
A static for requires static information for each sequence on the right-hand side of an each form to specialize the iteration statically.

For each of these forms, static mode is detected by checking the binding of #%dynamism using the scopes of form’s operator or identifier.

Other forms not provided by rhombus might also be sensitive to dynamic mode versus static mode. Macro implementations can use syntax_meta.is_static to determine a mode.

1	Rhombus Essentials
2	Collections and Iteration
3	Syntax Objects and Macros
4	Classes and Interfaces
5	Static Information and Binding
6	Core Reference
7	Meta and Macros Reference
8	Rhombus Static by Default
9	Libraries
10	Naming Conventions

6.1	General Forms
6.2	Definitions
6.3	Namespaces
6.4	Import
6.5	Export
6.6	Functions
6.7	Operators
6.8	Classes and Interfaces
6.9	Veneers
6.10	Mutable Variables and Assignment
6.11	Repetitions
6.12	Block
6.13	Conditionals
6.14	Matching
6.15	Iteration
6.16	Recursion
6.17	Context Parameters
6.18	Exceptions
6.19	Continuations
6.20	Implicit Forms
6.21	Static and Dynamic Lookup
6.22	Modules and Submodules
6.23	Booleans
6.24	Numbers
6.25	Characters
6.26	Strings
6.27	Keywords
6.28	Symbols
6.29	Byte Strings
6.30	Lists
6.31	Pairs and Pair Lists
6.32	Mutable Lists
6.33	Arrays
6.34	Maps
6.35	Sets
6.36	Boxes
6.37	Indexables
6.38	Listables
6.39	Sequences
6.40	Appendables
6.41	Comparables
6.42	Paths
6.43	Source Locations
6.44	Void
6.45	Equality
6.46	Dot
6.47	Multiple Values
6.48	Annotations
6.49	Enumerations
6.50	Input and Output
6.51	Eval
6.52	Syntax Objects
6.53	Syntax Classes
6.54	Simple Expression Macros
6.55	Unit Testing