Validate an AST node or model against the schema

Checks that a node's class is known, that every required field is present and non-NULL, and that it carries no field the schema does not declare.

Usage

validate_ast(x, path = "", recursive = TRUE)

Arguments

x

An AST node or a model.

path

Internal; the path reported in messages.

recursive

Logical; also check nested nodes (default TRUE).

Value

A character vector of problems, empty if x is valid.

Details

The same check runs automatically inside the constructors, so a malformed node is normally refused where it is built rather than surfacing later as a renderer that silently emits nothing - the trap described in CLAUDE.md. Use this function to check a model that already exists, for instance one read back from disk. Set options(multimod.validate = FALSE) to switch the constructor-time check off.

See also

ast_schema(), schema_type()

Examples

validate_ast(ast_expression("*", ast_symbol("a"), ast_symbol("b")))
#> character(0)

# a node missing a required field
bad <- ast_expression("*", ast_symbol("a"), ast_symbol("b"))
bad$rhs <- NULL
validate_ast(bad)
#> [1] " (expression): required field 'rhs' is missing"