scopefrom

Scopefrom is a conceptual feature used in static analysis and compiler design to identify the originating lexical scope for a given identifier or symbol. It describes the process of resolving where a name is defined and which declarations are in scope for a particular usage. The term is used in discussions of name binding, symbol resolution, and refactoring tools to distinguish the source scope from the current scope.

How scopefrom works: A scopefrom operation traces the scope chain from the usage upward through nested blocks or modules until it finds a binding that matches the identifier. It accounts for language-specific rules such as shadowing, imports, exports, and aliasing. In languages with module systems and closures, scopefrom helps determine whether a reference binds to a local variable, an outer-scope variable, or a module export. It is useful for editors performing code completion, for static analyzers identifying unbound identifiers, and for refactoring that moves or renames symbols.

Implementation considerations: In a compiler or analyzer, scopefrom is typically implemented with a symbol table stack or a scoped abstract syntax tree walker. The analysis must respect language constructs such as import statements, conditional definitions, and, where present, dynamic features that can alter binding at runtime. Limitations arise in languages with dynamic scope or runtime evaluation where static scope resolution cannot be guaranteed.

See also: lexical scope, static analysis, symbol resolution, shadowing, symbol table, module system.