From 6d58ce9bfef0acd608b898c1c58181a24cf7fa11 Mon Sep 17 00:00:00 2001 From: "gbracha@google.com" Date: Tue, 4 Mar 2014 18:37:37 +0000 Subject: [PATCH] Revise spec to agree with implementations for meaning of getter/variable and setter references. While the actual difference were only in a few odd cases, the new text should also be clearer. R=hausner@google.com, lrn@google.com Review URL: https://codereview.chromium.org//177283007 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@33287 260f80e4-7a28-3924-810f-c04153c831b5 --- docs/language/dartLangSpec.tex | 42 +++++++++++++++++++++------------- 1 file changed, 26 insertions(+), 16 deletions(-) diff --git a/docs/language/dartLangSpec.tex b/docs/language/dartLangSpec.tex index 23770e11ff4..094a9e3898f 100644 --- a/docs/language/dartLangSpec.tex +++ b/docs/language/dartLangSpec.tex @@ -3372,21 +3372,24 @@ An assignment changes the value associated with a mutable variable or property. Evaluation of an assignment $a$ of the form $v$ \code{=} $e$ proceeds as follows: -If there is neither a local variable declaration with name $v$ nor a setter declaration with name $v=$ in the lexical scope enclosing $a$, then: -\begin{itemize} - \item If $a$ occurs inside a top level or static function (be it function, method, getter, or setter) or variable initializer, evaluation of $a$ causes $e$ to be evaluated, after which a \code{NoSuchMethodError} is thrown. - \item Otherwise, the assignment is equivalent to the assignment \code{ \THIS{}.$v$ = $e$}. - \end{itemize} +%If there is neither a local variable declaration with name $v$ nor a setter declaration with name $v=$ in the lexical scope enclosing $a$, then: +%\begin{itemize} +% \item If $a$ occurs inside a top level or static function (be it function, method, getter, or setter) or variable initializer, evaluation of $a$ causes $e$ to be evaluated, after which a \code{NoSuchMethodError} is thrown. +% \item Otherwise, the assignment is equivalent to the assignment \code{ \THIS{}.$v$ = $e$}. +% \end{itemize} - Otherwise, let $d$ be the innermost declaration whose name is $v$, if it exists. +%Otherwise, -If $d$ is the declaration of a local variable, the expression $e$ is evaluated to an object $o$. Then, the variable $v$ is bound to $o$. -% unless $v$ is \FINAL{}, in which case a \code{NoSuchMethodError} is thrown (even if there is a noSuchMethod). -The value of the assignment expression is $o$. +Let $d$ be the innermost declaration whose name is $v$ or $v=$, if it exists. -If $d$ is the declaration of a library variable, the expression $e$ is evaluated to an object $o$. Then the setter $v=$ is invoked with its formal parameter bound to $o$. The value of the assignment expression is $o$. +If $d$ is the declaration of a local variable, the expression $e$ is evaluated to an object $o$. Then, the variable $v$ is bound to $o$ unless $v$ is \FINAL{} or \CONST{}, in which case a dynamic error occurs. +If no error occurs, the value of the assignment expression is $o$. -Otherwise, if $d$ is the declaration of a static variable in class $C$, then the assignment is equivalent to the assignment \code{$C.v$ = $e$}. +If $d$ is the declaration of a library variable, top level getter or top level setter, the expression $e$ is evaluated to an object $o$. Then the setter $v=$ is invoked with its formal parameter bound to $o$. The value of the assignment expression is $o$. + +Otherwise, if $d$ is the declaration of a static variable, static getter or static setter in class $C$, then the assignment is equivalent to the assignment \code{$C.v$ = $e$}. + +Otherwise, If $a$ occurs inside a top level or static function (be it function, method, getter, or setter) or variable initializer, evaluation of $a$ causes $e$ to be evaluated, after which a \code{NoSuchMethodError} is thrown. Otherwise, the assignment is equivalent to the assignment \code{ \THIS{}.$v$ = $e$}. @@ -3927,7 +3930,8 @@ Built-in identifiers are identifiers that are used as keywords in Dart, but are Evaluation of an identifier expression $e$ of the form $id$ proceeds as follows: -Let $d$ be the innermost declaration in the enclosing lexical scope whose name is $id$. If no such declaration exists in the lexical scope, let $d$ be the declaration of the inherited member named $id$ if it exists. + +Let $d$ be the innermost declaration in the enclosing lexical scope whose name is $id$ or $id=$. If no such declaration exists in the lexical scope, let $d$ be the declaration of the inherited member named $id$ if it exists. %If no such member exists, let $d$ be the declaration of the static member name $id$ declared in a superclass of the current class, if it exists. \begin{itemize} @@ -3945,8 +3949,8 @@ Let $d$ be the innermost declaration in the enclosing lexical scope whose name i \item If $d$ is a local variable or formal parameter then $e$ evaluates to the current binding of $id$. %\item If $d$ is a library variable, local variable, or formal parameter, then $e$ evaluates to the current binding of $id$. \commentary{This case also applies if d is a library or local function declaration, as these are equivalent to function-valued variable declarations.} \item If $d$ is a static method, top-level function or local function then $e$ evaluates to the function defined by $d$. -\item If $d$ is the declaration of a static variable or static getter declared in class $C$, then $e$ is equivalent to the getter invocation (\ref{getterInvocation}) $C.id$. -\item If $d$ is the declaration of a library variable or top-level getter, then $e$ is equivalent to the getter invocation $id$. +\item If $d$ is the declaration of a static variable, static getter or static setter declared in class $C$, then $e$ is equivalent to the getter invocation (\ref{getterInvocation}) $C.id$. +\item If $d$ is the declaration of a library variable, top-level getter or top-level setter, then $e$ is equivalent to the getter invocation $id$. \item Otherwise, if $e$ occurs inside a top level or static function (be it function, method, getter, or setter) or variable initializer, evaluation of $e$ causes a\code{NoSuchMethod} to be thrown. \item Otherwise, $e$ is equivalent to the property extraction (\ref{propertyExtraction}) \THIS{}.$id$. % This implies that referring to an undefined static getter by simple name is an error, whereas doing so by qualified name is only a warning. Same with assignments. Revise? @@ -3958,12 +3962,18 @@ The static type of $e$ is determined as follows: \item If $d$ is a class, type alias or type parameter the static type of $e$ is \code{Type}. \item If $d$ is a local variable or formal parameter the static type of $e$ is the type of the variable $id$, unless $id$ is known to have some type $T$, in which case the static type of $e$ is $T$, provided that $T$ is more specific than any other type $S$ such that $v$ is known to have type $S$. \item If $d$ is a static method, top-level function or local function the static type of $e$ the function type defined by $d$. -\item If $d$ is the declaration of a static variable or static getter declared in class $C$, the static type of $e$ the static type of the getter invocation (\ref{getterInvocation}) $C.id$. +\item If $d$ is the declaration of a static variable or static getter declared in class $C$, the static type of $e$ the static type of the getter invocation (\ref{getterInvocation}) $C.id$. \item If $d$ is the declaration of a library variable or top-level getter, the static type of $e$ is the static type of the getter invocation $id$. \item Otherwise, if $e$ occurs inside a top level or static function (be it function, method, getter, or setter) or variable initializer, the static type of $e$ is \DYNAMIC{}. \item Otherwise, the static type of $e$ is the type of the property extraction (\ref{propertyExtraction}) \THIS{}.$id$. \end{itemize} + \commentary{Note that if one declares a setter, we bind to the corresponding getter even if it does not exist.} + + \rationale{ + This prevents situations where one uses uncorrelated setters and getters. The intent is to prevent errors when a getter in a surrounding scope is used accidentally. + } + It is a static warning if an identifier expression $id$ occurs inside a top level or static function (be it function, method, getter, or setter) or variable initializer and there is no declaration $d$ with name $id$ in the lexical scope enclosing the expression. \subsection{ Type Test} @@ -4833,7 +4843,7 @@ It is a dynamic type error if $o$ is not of type \code{bool} or of type \code{Fu A Dart program consists of one or more libraries, and may be built out of one or more {\em compilation units}. A compilation unit may be a library or a part (\ref{parts}). -A library consists of (a possibly empty) set of imports, a set of exports, and a set of top-level declarations. A top-level declaration is either a class (\ref{classes}), a type alias declaration (\ref{typedef}), a function (\ref{functions}) or a variable declaration (\ref{variables}). The members of a library $L$ are those top level declarations given within a $L$. +A library consists of (a possibly empty) set of imports, a set of exports, and a set of top-level declarations. A top-level declaration is either a class (\ref{classes}), a type alias declaration (\ref{typedef}), a function (\ref{functions}) or a variable declaration (\ref{variables}). The members of a library $L$ are those top level declarations given within $L$. \begin{grammar} {\bf topLevelDefinition:}classDefinition;