Reflection

Usage

use Reflection;

Functions for finding out about fields, functions, and methods.

Note

There are several ways in which this module could be improved upon:

  • the methods here might be better as type methods, so you could use R.numFields() instead of numFields(R).
  • getField does not yet return a mutable value.
proc numFields(type t) param: int

Return the number of fields in a class or record as a param. The count of fields includes types and param fields.

proc getFieldName(type t, param i: int) param: string

Get the name of the ith field in a class or record. Causes a compilation error if i is not in 1..numFields(t).

Arguments:
  • t -- a class or record type
  • i -- which field to get the name of
Returns:

the name of the field, as a param string
proc getField(const ref x: ?t, param i: int) const ref

Get the ith field in a class or record. Causes a compilation error if i is not in 1..numFields(t).

Arguments:
  • x -- a class or record
  • i -- which field to get
Returns:

an rvalue referring to that field.
proc getField(const ref x: ?t, param s: string) const ref

Get a field in a class or record by name. Will generate a compilation error if a field with that name is not found.

Arguments:
  • x -- a class or record
  • s -- the name of a field
Returns:

an rvalue referring to that field.
proc getFieldRef(ref x: ?t, param i: int) ref

Get a mutable ref to the ith field in a class or record. Causes a compilation error if i is not in 1..numFields(t) or if the argument is not mutable.

Arguments:
  • x -- a class or record
  • i -- which field to get
Returns:

an rvalue referring to that field.
proc getFieldRef(ref x: ?t, param s: string) ref

Get a mutable ref to a field in a class or record by name. Will generate a compilation error if a field with that name is not found or if the class or record is not mutable.

Arguments:
  • x -- a class or record
  • s -- the name of a field
Returns:

an rvalue referring to that field.
proc getFieldIndex(type t, param s: string) param: int

Get a field index in a class or record, or 0 if the field is not found.

Arguments:
  • t -- a class or record type
  • s -- the name of a field
Returns:

an index i usable in getField, or 0 if the field was not found.
proc hasField(type t, param s: string) param: bool

Returns true if a class or record has a field named s, or false otherwise.

Arguments:
  • t -- a class or record type
  • s -- the name of a field
Returns:

true if the field is present.
proc canResolve(param fname: string) param: bool

Returns true if a function named fname taking no arguments could be called in the current scope.

proc canResolve(param fname: string, args ...) param: bool

Returns true if a function named fname taking the arguments in args could be called in the current scope.

proc canResolveMethod(obj, param fname: string) param: bool

Returns true if a method named fname taking no arguments could be called on obj in the current scope.

proc canResolveMethod(obj, param fname: string, args ...) param: bool

Returns true if a method named fname taking the arguments in args could be called on obj in the current scope.

proc canResolveTypeMethod(type t, param fname: string) param: bool

Returns true if a type method named fname taking no arguments could be called on type t in the current scope.

proc canResolveTypeMethod(type t, param fname: string, args ...) param: bool

Returns true if a type method named fname taking the arguments in args could be called on type t in the current scope.