The assign macro in this module is overloadable, and the openAssign template creates a NimNode that calls a forced open symbol of assign with the AST of the left hand side, AST of the right hand side, and the flag of whether or not it is a let, var, or mutating assignment. You can use the implementAssign and implementAssignExported templates as a shorthand for declaring these overloads.
Types
AssignBoundError = object of AssignError
- error for failed bound checks in assignments Source Edit
AssignContainsError = object of AssignError
- error for failed contains checks in assignments Source Edit
AssignEqualityError = object of AssignError
- error for failed equality checks in assignments Source Edit
AssignError = object of CatchableError
- any kind of check error in assignments Source Edit
AssignKind = enum akLet, akVar, akSet
- Propagated flag of how definitions should create assignments. Source Edit
AssignOptionError = object of AssignError
- error for failed contains checks in assignments Source Edit
Procs
proc defaultAssign(lhs, rhs: NimNode; kind = akLet): NimNode {....raises: [], tags: [].}
- The default interpretation of a definition. Source Edit
Templates
template assignCheckContains(a, b): untyped
- template for equality checks in assignments Source Edit
template assignCheckEqual(a, b): untyped
- template for equality checks in assignments Source Edit
template assignCheckGreater(a, b): untyped
- template for non-equality checks in assignments Source Edit
template assignCheckGreaterEqual(a, b): untyped
- template for non-equality checks in assignments Source Edit
template assignCheckLess(a, b): untyped
- template for non-equality checks in assignments Source Edit
template assignCheckLessEqual(a, b): untyped
- template for non-equality checks in assignments Source Edit
template assignCheckNotContains(a, b): untyped
- template for non-equality checks in assignments Source Edit
template assignCheckNotEqual(a, b): untyped
- template for non-equality checks in assignments Source Edit
template assignCheckNotType(a, b): untyped
- template for non-type checks in assignments Source Edit
template assignCheckOption(a): untyped
- template for equality checks in assignments Source Edit
template assignCheckType(a, b): untyped
- template for type checks in assignments Source Edit
template implementAssign(T; body) {.dirty.}
-
Implements an overload (non-exported) of assign for T with the macro body being body. Macro argument names in order are lhs, rhs and kind. Has shorthand aliases open and default for openAssign and defaultAssign respectively.
Example:
import std/macros type LinkedList[T] {.acyclic.} = ref object leaf: T next: LinkedList[T] implementAssign LinkedList: let newLhs = if lhs.kind == nnkBracket and lhs.len == 1: lhs[0] else: lhs if newLhs.kind == nnkInfix and newLhs[0].eqIdent"|": newStmtList( open(newLhs[1], newDotExpr(rhs, ident"leaf")), open(newLhs[2], newDotExpr(rhs, ident"next"))) else: default() let a = LinkedList[int](leaf: 1, next: LinkedList[int](leaf: 2, next: LinkedList[int](leaf: 3, next: nil))) import ./syntax x | [y | [z | _]] := a doAssert (x, y, z) == (1, 2, 3)
Source Edit template implementAssignExported(T; body) {.dirty.}
- Same as implementAssign but exports the generated macro. Source Edit
template openAssign(lhs, rhs: NimNode; ak: AssignKind = akLet): NimNode
- Creates a node that calls an open symbol assign with lhs and rhs. Source Edit