lean4-htt/library/init/lean/compiler/initattr.lean
Leonardo de Moura 697f69020f fix(library/init/lean/parser/parser): new registerBuiltinParserAttribute
It is still broken since we apply attributes before we compile code.

Recall that attributes such as `@[export]` and `@[extern]` must be applied before we
compile code.

On the other hand, any attribute `attrName`
```
@[attrName] def foo := ...
```
which creates auxiliary definitions that depend on `foo` must be applied
AFTER we generate code for `foo`. Otherwise, we will fail to compile the
auxiliary definition since we don't have code for `foo` yet.

I will fix the issue above by allowing attributes to specify when they
should be applied. I will start with only two options: before and after
code compilation. In the future, we may need more options (e.g., before
elaboration), but I don't see the need yet.

cc @kha
2019-06-19 09:52:56 -07:00

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/-
Copyright (c) 2019 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura
-/
prelude
import init.lean.environment
import init.lean.attributes
namespace Lean
private def getIOTypeArg : Expr → Option Expr
| (Expr.app (Expr.const `IO _) arg) := some arg
| _ := none
private def isUnitType : Expr → Bool
| (Expr.const `Unit _) := true
| _ := false
private def isIOUnit (type : Expr) : Bool :=
match getIOTypeArg type with
| some type := isUnitType type
| _ := false
def mkInitAttr : IO (ParametricAttribute Name) :=
registerParametricAttribute `init "initialization procedure for global references" $ λ env declName stx,
match env.find declName with
| none := Except.error "unknown declaration"
| some decl :=
match stx with
| Syntax.ident _ _ initFnName _ _ :=
match env.find initFnName with
| none := Except.error ("unknown initialization function '" ++ toString initFnName ++ "'")
| some initDecl :=
match getIOTypeArg initDecl.type with
| none := Except.error ("initialization function '" ++ toString initFnName ++ "' must have type of the form `IO <type>`")
| some initTypeArg :=
if decl.type == initTypeArg then Except.ok initFnName
else Except.error ("initialization function '" ++ toString initFnName ++ "' type mismatch")
| Syntax.missing :=
if isIOUnit decl.type then Except.ok Name.anonymous
else Except.error "initialization function must have type `IO Unit`"
| _ := Except.error "unexpected kind of argument"
@[init mkInitAttr]
constant initAttr : ParametricAttribute Name := default _
def isIOUnitInitFn (env : Environment) (fn : Name) : Bool :=
match initAttr.getParam env fn with
| some Name.anonymous := true
| _ := false
@[export lean.get_init_fn_name_for_core]
def getInitFnNameFor (env : Environment) (fn : Name) : Option Name :=
match initAttr.getParam env fn with
| some Name.anonymous := none
| some n := some n
| _ := none
def hasInitAttr (env : Environment) (fn : Name) : Bool :=
(getInitFnNameFor env fn).isSome
def setInitAttr (env : Environment) (declName : Name) (initFnName : Name := Name.anonymous) : Except String Environment :=
initAttr.setParam env declName initFnName
end Lean