Let a method name itself in JS with <jsName:>

README.md

@@ -23,7 +23,15 @@ QJSRuntime during: [ :context |
 	context eval: 'grid.name() + " has " + grid.rowAt_(1)' ]
 ```
 
-Only the selectors you list exist in JS, named PharoJS-style: `#rowAt:` becomes `rowAt_`, and `#at:put:` becomes `at_put_`. To decide what JS may do with objects that come back from those calls, give a table of classes instead:
+Only the selectors you list exist in JS. Their names in JS are a separate matter: a method can name itself with a pragma,
+
+```smalltalk
+at: key put: value
+	<jsName: 'atPut'>
+	...
+```
+
+so JS calls `grid.atPut(key, value)`. Without a pragma the name is PharoJS-style: `#rowAt:` becomes `rowAt_`, and `#at:put:` becomes `at_put_`. The pragma names the method, it does not expose it; two exposed selectors with the same name in one binding signal a `QJSError`. To decide what JS may do with objects that come back from those calls, give a table of classes instead:
 
 ```smalltalk
 context at: 'grid' put: aGrid exposing: {

src/QuickJS-Core/QJSBinding.class.st

@@ -1,15 +1,18 @@
 "
-I am what a runtime keeps for a Pharo object it has handed to JS: the object, the selectors JS may call on it, and the exposure table that decides the selectors of every object coming back from those calls.
+I am what a runtime keeps for a Pharo object it has handed to JS: the object, the selectors JS may call on it, their names in JS, and the exposure table that decides the selectors of every object coming back from those calls.
 
-The exposure table maps classes to selectors. An object gets the selectors of the nearest class in its hierarchy that has an entry; without an entry it gets none and stays opaque to JS.
+The exposure table maps classes to selectors. An object gets the selectors of the nearest class in its hierarchy that has an entry; without an entry it gets none and stays opaque to JS. That is the permission.
+
+The name is separate from the permission: a method names itself with a pragma, e.g. `at: key put: value <jsName: 'atPut'>`; without one, the name is PharoJS-style (#at:put: becomes at_put_). Two exposed selectors with the same name signal a QJSError.
 "
 Class {
 	#name : 'QJSBinding',
 	#superclass : 'Object',
 	#instVars : [
 		'object',
 		'exposure',
-		'selectors'
+		'selectors',
+		'names'
 	],
 	#category : 'QuickJS-Core',
 	#package : 'QuickJS-Core'
@@ -21,6 +24,13 @@ QJSBinding class >> object: anObject exposure: aDictionary [
 	^ self new setObject: anObject exposure: aDictionary
 ]
 
+{ #category : 'naming' }
+QJSBinding class >> pharoJSNameOf: aSelector [
+	"#at:put: becomes at_put_"
+
+	^ aSelector copyReplaceAll: ':' with: '_'
+]
+
 { #category : 'testing' }
 QJSBinding >> allows: aSelector [
 
@@ -33,6 +43,27 @@ QJSBinding >> exposure [
 	^ exposure
 ]
 
+{ #category : 'naming' }
+QJSBinding >> jsNameOf: aSelector [
+	"The name the method the object runs for aSelector gives itself with <jsName:>, otherwise the PharoJS-style name"
+
+	| name |
+	(object class lookupSelector: aSelector) ifNotNil: [ :method |
+		(method pragmaAt: #jsName:) ifNotNil: [ :pragma |
+			name := pragma arguments first.
+			(name isString and: [ name notEmpty ]) ifFalse: [
+				QJSError signal: '<jsName:> of ' , method printString , ' must be a non-empty string' ].
+			^ name asString ] ].
+	^ self class pharoJSNameOf: aSelector
+]
+
+{ #category : 'accessing' }
+QJSBinding >> names [
+	"JS names to the selectors they call"
+
+	^ names
+]
+
 { #category : 'accessing' }
 QJSBinding >> object [
 
@@ -45,6 +76,18 @@ QJSBinding >> selectors [
 	^ selectors
 ]
 
+{ #category : 'initialization' }
+QJSBinding >> setNames [
+
+	names := Dictionary new.
+	selectors do: [ :each |
+		| name |
+		name := self jsNameOf: each.
+		names at: name ifPresent: [ :other |
+			QJSError signal: 'JS name ' , name , ' is used by both #' , other , ' and #' , each ].
+		names at: name put: each ]
+]
+
 { #category : 'initialization' }
 QJSBinding >> setObject: anObject exposure: aDictionary [
 
@@ -53,5 +96,6 @@ QJSBinding >> setObject: anObject exposure: aDictionary [
 	selectors := anObject class withAllSuperclasses
 		             detect: [ :each | aDictionary includesKey: each ]
 		             ifFound: [ :each | aDictionary at: each ]
-		             ifNone: [ #(  ) ]
+		             ifNone: [ #(  ) ].
+	self setNames
 ]

src/QuickJS-Core/QJSContext.class.st

@@ -1,7 +1,7 @@
 "
 I am a QuickJS context: a global object in a runtime. #eval: runs a script and answers its result as a Pharo value; a JS exception is signalled as a QJSError.
 
-Values cross in both directions the same way: nil and null (undefined becomes nil too), Booleans, numbers as Integer or Float, strings, sequenceable collections and arrays, dictionaries and plain objects. Every other Pharo object reaches JS as a binding: a JS object with one method per exposed selector, named PharoJS-style (#at:put: becomes at_put_). A binding coming back from JS is the Pharo object itself.
+Values cross in both directions the same way: nil and null (undefined becomes nil too), Booleans, numbers as Integer or Float, strings, sequenceable collections and arrays, dictionaries and plain objects. Every other Pharo object reaches JS as a binding: a JS object with one method per exposed selector. A method names itself in JS with a pragma (`at: key put: value <jsName: 'atPut'>`); without one the name is PharoJS-style (#at:put: becomes at_put_). Which selectors are exposed and what they are called are separate (see QJSBinding). A binding coming back from JS is the Pharo object itself.
 
 	context at: 'grid' put: aGrid exposing: #(name rows).
 	context at: 'grid' put: aGrid exposing: { AGGrid -> #(name rows). AGRow -> #(id name) }.
@@ -113,8 +113,8 @@ QJSContext >> bindingBoxFor: anObject exposure: aDictionary [
 	binding := QJSBinding object: anObject exposure: aDictionary.
 	id := runtime registerBinding: binding.
 	box := self library context: handle newBinding: id.
-	binding selectors do: [ :each |
-		self library context: handle define: box name: (self jsNameOf: each) id: id selector: each ].
+	binding names keysAndValuesDo: [ :name :selector |
+		self library context: handle define: box name: name id: id selector: selector ].
 	^ box
 ]
 
@@ -245,13 +245,6 @@ QJSContext >> isLive [
 	^ self isFromThisSession and: [ (self library contextIsLive: handle) = 1 ]
 ]
 
-{ #category : 'private - to JS' }
-QJSContext >> jsNameOf: aSelector [
-	"PharoJS-style: #at:put: becomes at_put_"
-
-	^ aSelector copyReplaceAll: ':' with: '_'
-]
-
 { #category : 'accessing' }
 QJSContext >> library [
 

src/QuickJS-Tests/QJSBindingTest.class.st

@@ -77,13 +77,34 @@ QJSBindingTest >> testFollowUpObjectsUseTheTable [
 	self assert: (context eval: 'grid.rowAt_(2).name()') equals: 'b'
 ]
 
+{ #category : 'tests' }
+QJSBindingTest >> testInheritedPragmaAndOverrideWithout [
+	"The name comes from the method the object runs: #at:put: inherited with its pragma, #at: overridden without one"
+
+	context
+		at: 'grid'
+		put: (QJSTestSubGrid named: 'Kunden' rows: #(  ))
+		exposing: { (QJSTestGrid -> #( at:put: at: )) }.
+	self assert: (context eval: 'grid.atPut("k", 4); grid.at_("k")') equals: 40.
+	self assert: (context eval: 'typeof grid.get') equals: 'undefined'
+]
+
 { #category : 'tests' }
 QJSBindingTest >> testKeywordSelectorIsNamedLikePharoJS [
 
 	context at: 'grid' put: grid exposing: #( rowAt: ).
 	self assert: (context eval: 'typeof grid.rowAt_') equals: 'function'
 ]
 
+{ #category : 'tests' }
+QJSBindingTest >> testNameAloneDoesNotExpose [
+	"Naming and permission are separate: a method with <jsName:> that is not exposed does not exist in JS"
+
+	context at: 'grid' put: grid exposing: #( name ).
+	self assert: (context eval: 'typeof grid.atPut') equals: 'undefined'.
+	self assert: (context eval: 'typeof grid.at_put_') equals: 'undefined'
+]
+
 { #category : 'tests' }
 QJSBindingTest >> testNestedEvaluationFromPharo [
 
@@ -92,6 +113,15 @@ QJSBindingTest >> testNestedEvaluationFromPharo [
 	self assert: (context eval: 'grid.nested() + 1') equals: 43
 ]
 
+{ #category : 'tests' }
+QJSBindingTest >> testPragmaNamesTheMethod [
+
+	context at: 'grid' put: grid exposing: #( at:put: at: rowAt: ).
+	self assert: (context eval: 'grid.atPut("k", 42); grid.get("k")') equals: 42.
+	self assert: (context eval: 'typeof grid.at_put_') equals: 'undefined'.
+	self assert: (context eval: 'typeof grid.rowAt_') equals: 'function'
+]
+
 { #category : 'tests' }
 QJSBindingTest >> testPharoErrorBecomesJSError [
 
@@ -125,6 +155,16 @@ QJSBindingTest >> testReleasedBindingsAreDropped [
 	self assert: runtime bindingCount equals: 0
 ]
 
+{ #category : 'tests' }
+QJSBindingTest >> testTwoSelectorsWithOneNameAreRefused [
+
+	self
+		should: [ context at: 'grid' put: grid exposing: #( name nameAgain ) ]
+		raise: QJSError
+		withExceptionDo: [ :error | self assert: (error messageText includesSubstring: 'JS name name') ].
+	self assert: runtime bindingCount equals: 0
+]
+
 { #category : 'tests' }
 QJSBindingTest >> testUnexposedSelectorDoesNotExist [
 

src/QuickJS-Tests/QJSTestGrid.class.st

@@ -7,7 +7,8 @@ Class {
 	#instVars : [
 		'name',
 		'rows',
-		'context'
+		'context',
+		'values'
 	],
 	#category : 'QuickJS-Tests',
 	#package : 'QuickJS-Tests'
@@ -19,6 +20,20 @@ QJSTestGrid class >> named: aString rows: names [
 	^ self new setName: aString rows: names
 ]
 
+{ #category : 'accessing' }
+QJSTestGrid >> at: aKey [
+
+	<jsName: 'get'>
+	^ values at: aKey ifAbsent: [ nil ]
+]
+
+{ #category : 'accessing' }
+QJSTestGrid >> at: aKey put: aValue [
+
+	<jsName: 'atPut'>
+	^ values at: aKey put: aValue
+]
+
 { #category : 'accessing' }
 QJSTestGrid >> context: aContext [
 
@@ -49,6 +64,14 @@ QJSTestGrid >> name [
 	^ name
 ]
 
+{ #category : 'accessing' }
+QJSTestGrid >> nameAgain [
+	"Takes a name another selector already has"
+
+	<jsName: 'name'>
+	^ name
+]
+
 { #category : 'accessing' }
 QJSTestGrid >> nested [
 	"Evaluates JS while JS is calling this method"
@@ -78,5 +101,6 @@ QJSTestGrid >> secret [
 QJSTestGrid >> setName: aString rows: names [
 
 	name := aString.
-	rows := names collect: [ :each | QJSTestRow named: each ]
+	rows := names collect: [ :each | QJSTestRow named: each ].
+	values := Dictionary new
 ]

src/QuickJS-Tests/QJSTestSubGrid.class.st

@@ -0,0 +1,15 @@
+"
+A stand-in that inherits #at:put: with its <jsName:> and overrides #at: without one.
+"
+Class {
+	#name : 'QJSTestSubGrid',
+	#superclass : 'QJSTestGrid',
+	#category : 'QuickJS-Tests',
+	#package : 'QuickJS-Tests'
+}
+
+{ #category : 'accessing' }
+QJSTestSubGrid >> at: aKey [
+
+	^ (super at: aKey) ifNotNil: [ :value | value * 10 ]
+]