DME — Code Reflection

class DME

The DME class provides reflection information for a BYOND project. This includes looking up available types, proc and var names on those types, and basic support for AST walking.

DME instances are created with the following methods:

static from_file(filename: str | os.PathLike[str], parse_procs=False) → DME

Read the BYOND environment from the filename referring to a “.dme” file. If the optional parse_procs argument is True, reflection data is made available for all procs.

Raises:

OSError: If the file is not found or there was an error opening it.

Raises:

RuntimeError: If there was an error parsing the DME environment.

Once instantiated, the following properties and methods are available:

property types: dict[Path, TypeDecl]

A mapping of type paths to their TypeDecls.

typesof(prefix: Path | str) → list[Path]

Return a list of Paths which include the type prefix and any of its subtypes.

subtypesof(prefix: Path | str) → list[Path]

Return a list of Paths of any subtypes of prefix, excluding itself.

class ProcDecl

A declaration for a specific proc on a type. Note that a type may have multiple definitions of a given proc with the same name. This only represents one proc definition.

property source_loc: SourceLoc

The SourceLoc of the proc’s declaration, as determined by the parser.

walk(walker)

Use the AST walker to walk this proc.

The argument walker is expected to be a Python object which exposes methods for each kind of AST node you wish to visit. Each method should take two arguments: node, which will be filled in with information about that node in the AST, and source_loc, which includes lexical information about the AST node, such as line, column, and filename. The currently available visitors are:

  • visit_AssignOp

  • visit_BinaryOp

  • visit_Break

  • visit_Call

  • visit_Constant

  • visit_Continue

  • visit_Crash

  • visit_Del

  • visit_DoWhile

  • visit_DynamicCall

  • visit_Expr

  • visit_ExternalCall

  • visit_Field

  • visit_ForInfinite

  • visit_ForKeyValue

  • visit_ForList

  • visit_ForLoop

  • visit_ForRange

  • visit_Goto

  • visit_Identifier

  • visit_If

  • visit_Index

  • visit_Input

  • visit_InterpString

  • visit_Label

  • visit_List

  • visit_Locate

  • visit_NewImplicit

  • visit_NewMiniExpr

  • visit_NewPrefab

  • visit_ParentCall

  • visit_Pick

  • visit_ProcReference

  • visit_Return

  • visit_SelfCall

  • visit_Setting

  • visit_StaticField

  • visit_Switch

  • visit_TernaryOp

  • visit_Throw

  • visit_TryCatch

  • visit_UnaryOp

  • visit_Var

  • visit_While

As with ast.NodeVisitor, child nodes of a custom visitor method will not be visited. There is currently no analogous generic_visit support.

class VarDecl

The VarDecl class returns basic information about a variable declared on a TypeDecl type declaration.

property name: str

The name of the variable.

property declared_type: Path | None

The type of the variable, if available and declared.

property const_val: any | None

The initial value of the variable, if expressable as a constant.

class TypeDecl

The TypeDecl class returns basic information about a type declared in the DME file.

property path: Path

The path of the type.

property source_loc: SourceLoc

The SourceLoc of the type’s initial declaration, as determined by the parser.

proc_decls(name=None) → list[ProcDecl]

Returns a list of ProcDecls for the type. If name is set, only proc declarations with that name will be returned.

proc_names(self, declared=False, modified=False, unmodified=False) → list[str]

Returns a list of proc names associated with the type. At least one of the arguments must be true:

  • If declared is true, the list of proc names will include names declared on the type directly.

  • If modified is true, the list of proc names will include names of proc declared on a parent type but changed by this type.

  • if unmodified is true, the list of proc names will include names of proc which were declared on a parent type and unchanged by this type.

var_decl(name: str, parents: bool = True) → VarDecl

Returns the variable declaration of the var name. If parents is True, the type’s parents will be checked for a variable declaration if not specified on the current type.

var_names(self, declared=False, modified=False, unmodified=False) → list[str]

Returns a list of variables names for the type declaration.

At least one of the arguments must be true:

  • If declared is true, the list of variable names will include names declared on the type directly.

  • If modified is true, the list of variable names will include names of variables declared on a parent type but changed by this type.

  • if unmodified is true, the list of variable names will include names of variables which were declared on a parent type and unchanged by this type.