Added 'new_class' instead of 'new' for the macro.
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Joey Payne
parent
e3d9812afe
commit
321be06f40
2 changed files with 95 additions and 20 deletions
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@ -6,9 +6,13 @@ These extensions aim to improve the usability of nim in practical applications.
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Extensions so far include:
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## OOP macro
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This module was modified from the OOP section on the excellent website http://nim-by-example.github.io/
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usage:
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```nim
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import oop_macro
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class BaseObject: # inherits from RootObj
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# attributes/properties
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var
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@ -26,3 +30,8 @@ Extensions so far include:
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method override_me(argx: float): int=
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result = int(self.y) + int(argx) + self.x
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```
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There's also an example in the code that demonstrates the inheritance that can be run by executing:
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```bash
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nim c -r oop_macro.nim
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```
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106
oop_macro.nim
106
oop_macro.nim
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@ -1,23 +1,26 @@
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import macros
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import strutils
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{.hint[XDeclaredButNotUsed]: off.}
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macro new*(obj: expr): expr {.immediate.}=
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## Replaces the new keyword to call an init
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## function if it exists
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macro new_class*(obj: untyped): untyped=
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## Creates a new instance of the class
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## and calls the init() method on it
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quote do:
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var init_obj = `obj`
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when compiles(init_obj.init()):
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init_obj.init()
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init_obj
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macro class*(head: expr, body: stmt): stmt {.immediate.} =
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macro class*(head: untyped, body: untyped): untyped=
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# The macro is immediate so that it doesn't
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# resolve identifiers passed to it
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# object reference name inside methods.
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# ie: self, self
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let obj_reference = "self"
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var export_class: bool = false # whether or not to export the class to other modules
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var typeName, baseName: PNimrodNode
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@ -39,6 +42,21 @@ macro class*(head: expr, body: stmt): stmt {.immediate.} =
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typeName = head[1]
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baseName = head[2]
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elif head.kind == nnkInfix and $head[0] == "*" and $head[1] == "of":
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# echo head.treeRepr
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# -----------
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# Infix
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# Ident !"*"
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# Ident !"Animal"
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# Prefix
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# Ident !"of"
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# Ident !"RootObj"
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export_class = true
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typeName = head[1]
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baseName = head[2][1]
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elif head.kind == nnkInfix and $head[0] == "*":
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export_class = true
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typeName = head[1]
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else:
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quit "Invalid node: " & head.lispRepr
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@ -106,10 +124,22 @@ macro class*(head: expr, body: stmt): stmt {.immediate.} =
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# forward declare the inheritable method
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let n2 = copyNimTree(n)
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let proc_name = $(n2.name.toStrLit())
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let type_name = $(typeName.toStrLit())
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let new_name = ident(proc_name & type_name)
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n2.name = new_name
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var proc_name = ""
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if n2.name.kind == nnkIdent:
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proc_name = $(n2.name.toStrLit())
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n2.name = ident(proc_name & type_name)
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elif n2.name.kind == nnkPostFix:
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if n2.name[1].kind == nnkIdent:
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proc_name = $(n2.name[1].toStrLit())
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n2.name[1] = ident(proc_name & type_name)
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elif n2.name[1].kind == nnkAccQuoted:
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proc_name = $(n2.name[1][0].toStrLit())
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n2.name[1][0] = ident(proc_name & type_name)
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elif n2.name.kind == nnkAccQuoted:
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proc_name = $(n2.name[0].toStrLit())
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n2.name[0] = ident(proc_name & type_name)
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result.add(n2)
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else:
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discard
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@ -127,10 +157,25 @@ macro class*(head: expr, body: stmt): stmt {.immediate.} =
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# ie: procName_ClassName()
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let n2 = copyNimTree(node)
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n2.params.insert(1, newIdentDefs(ident(obj_reference), typeName))
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let proc_name = $(n2.name.toStrLit())
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let type_name = $(typeName.toStrLit())
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let new_name = ident(proc_name & type_name)
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n2.name = new_name
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var proc_name = $(n2.name.toStrLit())
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var is_assignment = proc_name.contains("=")
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if n2.name.kind == nnkIdent:
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proc_name = $(n2.name.toStrLit())
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n2.name = ident(proc_name & type_name)
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elif n2.name.kind == nnkPostFix:
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if n2.name[1].kind == nnkIdent:
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proc_name = $(n2.name[1].toStrLit())
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n2.name[1] = ident(proc_name & type_name)
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elif n2.name[1].kind == nnkAccQuoted:
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proc_name = $(n2.name[1][0].toStrLit())
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n2.name[1][0] = ident(proc_name & type_name)
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elif n2.name.kind == nnkAccQuoted:
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proc_name = $(n2.name[0].toStrLit())
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n2.name[0] = ident(proc_name & type_name)
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result.add(n2)
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# simply call the class method from here
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@ -139,7 +184,11 @@ macro class*(head: expr, body: stmt): stmt {.immediate.} =
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var p: seq[PNimrodNode] = @[]
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for i in 1..n.params.len-1:
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p.add(n.params[i][0])
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n.body = newStmtList(newCall(proc_name & type_name, p))
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if is_assignment:
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let dot = newDotExpr(ident(obj_reference), ident(proc_name & type_name))
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n.body = newStmtList(newAssignment(dot, p[1]))
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else:
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n.body = newStmtList(newCall(proc_name & type_name, p))
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result.add(n)
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@ -174,11 +223,19 @@ macro class*(head: expr, body: stmt): stmt {.immediate.} =
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var type_decl: PNimrodNode
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if baseName == nil:
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type_decl = quote do:
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type `typeName` = ref object of RootObj
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if export_class:
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type_decl = quote do:
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type `typeName`* = ref object of RootObj
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else:
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type_decl = quote do:
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type `typeName` = ref object of RootObj
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else:
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type_decl = quote do:
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type `typeName` = ref object of `baseName`
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if export_class:
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type_decl = quote do:
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type `typeName`* = ref object of `baseName`
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else:
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type_decl = quote do:
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type `typeName` = ref object of `baseName`
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# Inspect the tree structure:
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#
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@ -199,7 +256,7 @@ macro class*(head: expr, body: stmt): stmt {.immediate.} =
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result.insert(0, type_decl)
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class Animal of RootObj:
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class Animal* of RootObj: #exports the class. Need to use RootObj for exports
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var name: string
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var age: int
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method stuff(s:string): string = s
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@ -220,14 +277,23 @@ class Tiger of Cat:
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echo "I am a new tiger"
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method vocalize: string =
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# no need for super.super!
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self.vocalize_animal() & "Rawr!"
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self.vocalize_animal() & "Rawr!" & self.vocalize_cat()
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if isMainModule:
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var animals: seq[Animal] = @[]
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animals.add(new(Dog(name: "Sparky", age: 10)))
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animals.add(new(Cat(name: "Mitten", age: 10)))
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animals.add(new(Tiger(name: "Jean", age: 2)))
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animals.add(new_class(Dog(name: "Sparky", age: 10)))
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animals.add(new_class(Cat(name: "Mitten", age: 10)))
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animals.add(new_class(Tiger(name: "Jean", age: 2)))
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for a in animals:
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echo a.name, " says ", a.vocalize()
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echo a.age_human_yrs()
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# prints:
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# I am a new tiger
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# Sparky says woof
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# 70
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# Mitten says ...meow
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# 10
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# Jean says ...Rawr!...meow
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# 2
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