From 997851e681669439d01ad52457576e3370e1a9e4 Mon Sep 17 00:00:00 2001 From: Robert Griesemer Date: Fri, 25 Sep 2009 15:36:25 -0700 Subject: [PATCH] - reworked section on import declarations - added missing

tags in various places DELTA=62 (32 added, 4 deleted, 26 changed) OCL=35014 CL=35014 --- doc/go_spec.html | 78 ++++++++++++++++++++++++++++++++---------------- 1 file changed, 53 insertions(+), 25 deletions(-) diff --git a/doc/go_spec.html b/doc/go_spec.html index c265661e10..4255fec42b 100644 --- a/doc/go_spec.html +++ b/doc/go_spec.html @@ -1266,7 +1266,7 @@ can be represented accurately as a value of type T.

The predeclared identifier nil is assignment compatible with any pointer, function, slice, map, channel, or interface type and -represents the zero value for that type. +represents the zero value for that type.

@@ -1417,7 +1417,7 @@ the entity declared by the inner declaration.

The package clause is not a declaration; the package name does not appear in any scope. Its purpose is to identify the files belonging -to the same package and to specify the default name for import +to the same package and to specify the default package name for import declarations.

@@ -1694,14 +1694,18 @@ var s = "OMDB" // s has type string

Short variable declarations

+

A short variable declaration uses the syntax: +

 ShortVarDecl = IdentifierList ":=" ExpressionList .
+

It is a shorthand for a regular variable declaration with initializer expressions but no types: +

 "var" IdentifierList = ExpressionList .
@@ -1836,7 +1840,9 @@ operators and functions to operands.
 
 
Operands

 
+

 Operands denote the elementary values in an expression.
+

 
 
 Operand    = Literal | QualifiedIdent | MethodExpr | "(" Expression ")" .
@@ -3009,9 +3015,9 @@ respectively. Except for shift operations, if the operands of a binary operation
 are an untyped integer constant and an untyped floating-point constant,
 the integer constant is converted to an untyped floating-point constant
 (relevant for / and %).
-

-
 

+
+

 Applying an operator to untyped constants results in an untyped
 constant of the same kind (that is, a boolean, integer, floating-point, or
 string constant), except for
@@ -4170,34 +4176,42 @@ An implementation may require that all source files for a package inhabit the sa
 
Import declarations

 
 

-A source file gains access to exported identifiers
-from another package through an import declaration.
-In the general form, an import declaration provides an identifier
-that code in the source file may use to access the imported package's
-contents and a file name referring to the (compiled) implementation of
-the package.  The file name may be relative to a repository of
-installed packages.
+An import declaration states that the current package depends on the
+imported package and provides acccess to its
+exported identifiers.
+

+
+

+The import declaration binds a package name to the imported package (except in
+the case of . or _ imports; see below). The package name
+denotes the imported package within the current source file. If no explicit
+package name is present, the package name defined within the source
+files of the imported package is used.
+

+
+

+The imported package is specified by an import path; the meaning of the path
+is implementation-dependent. It may be a file name relative to a repository
+of installed packages and the file a (compiled) implementation of the package.
 

 
 
 ImportDecl       = "import" ( ImportSpec | "(" [ ImportSpecList ] ")" ) .
 ImportSpecList   = ImportSpec { ";" ImportSpec } [ ";" ] .
-ImportSpec       = [ "." | PackageName ] PackageFileName .
-PackageFileName  = StringLit .
+ImportSpec       = [ "." | PackageName ] ImportPath .
+ImportPath       = StringLit .
 

 
 

-After an import, in the usual case an exported name N from the imported
-package P may be accessed by the qualified identifier
-P.N (§Qualified identifiers).  The actual
-name P depends on the form of the import declaration.  If
-an explicit package name p1 is provided, the qualified
-identifer will have the form p1.N.  If no name
-is provided in the import declaration, P will be the package
-name declared within the source files of the imported package.
+If a package A is imported by a package P and
+A exports an identifier X, then X
+may be referred to by the qualified identifier
+A.X within P. If an explicit package name
+B is present, X must be referred to as B.X.
 Finally, if the import declaration uses an explicit period
-(.) for the package name, N will be declared
-in the current file's file block and can be accessed without a qualifier.
+(.) for the package name, X will be declared
+in the current file's file block and can be accessed
+without a qualifier.
 

 
 

@@ -4208,13 +4222,25 @@ installed the compiled package in file
 

 
 
-Import syntax               Local name of Sin
+Import declaration          Local name of Sin
 
-import M "lib/math"         M.Sin
 import   "lib/math"         math.Sin
+import M "lib/math"         M.Sin
 import . "lib/math"         Sin
 

 
+

+It is illegal for a package to import itself or to import a package without
+referring to any of its exported identifiers. To import a package solely for
+its side-effects (initialization), use the blank
+identifier as explicit package name:
+

+
+
+import _ "lib/math"
+

+
+
 
Multiple-file packages

 
 

@@ -4500,7 +4526,9 @@ provides a safe, more convenient way to inspect interface values.
 
 
Size and alignment guarantees

 
+

 For the numeric types (§Numeric types), the following sizes are guaranteed:
+

 
 
 type                      size in bytes
-- 
2.48.1