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- assignments to structs are only legal if all struct fields are visible

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- removed section on Multiple-file packages as this seems now now covered
  sufficiently elsewhere

DELTA=45  (11 added, 25 deleted, 9 changed)
OCL=35065
CL=35071
This commit is contained in:
Robert Griesemer 2009-09-28 19:21:15 -07:00
parent dd64f86e08
commit 326ef13976
1 changed files with 20 additions and 34 deletions
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54
doc/go_spec.html
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@ -1256,6 +1256,14 @@ with compatible element type and at least one of <code>V</code> or <code>T</code
</li> </li>
</ul> </ul>
<p>
If <code>T</code> is a struct type, either all fields of <code>T</code>
must be <a href="#Exported_identifiers">exported</a>, or the assignment must be in
the same package in which <code>T</code> is declared.
In other words, a struct value can be assigned to a struct variable only if
every field of the struct may be legally assigned individually by the program.
</p>
<p> <p>
An untyped <a href="#Constants">constant</a> <code>v</code> An untyped <a href="#Constants">constant</a> <code>v</code>
is assignment compatible with type <code>T</code> if <code>v</code> is assignment compatible with type <code>T</code> if <code>v</code>
@ -1946,7 +1954,7 @@ Value = Expression .
The LiteralType must be a struct, array, slice, or map type The LiteralType must be a struct, array, slice, or map type
(the grammar enforces this constraint except when the type is given (the grammar enforces this constraint except when the type is given
as a TypeName). as a TypeName).
The types of the expressions must be <a href="#Assignment_compatibility">assignment compatible</a> to The types of the expressions must be <a href="#Assignment_compatibility">assignment compatible</a> with
the respective field, element, and key types of the LiteralType; the respective field, element, and key types of the LiteralType;
there is no additional conversion. there is no additional conversion.
The key is interpreted as a field name for struct literals, The key is interpreted as a field name for struct literals,
@ -2466,7 +2474,7 @@ f(a1, a2, ... an)
<p> <p>
calls <code>f</code> with arguments <code>a1, a2, ... an</code>. calls <code>f</code> with arguments <code>a1, a2, ... an</code>.
The arguments must be single-valued expressions The arguments must be single-valued expressions
<a href="#Assignment_compatibility">assignment compatible</a> with the parameters of <a href="#Assignment_compatibility">assignment compatible</a> with the parameter types of
<code>F</code> and are evaluated before the function is called. <code>F</code> and are evaluated before the function is called.
The type of the expression is the result type The type of the expression is the result type
of <code>F</code>. of <code>F</code>.
@ -3628,7 +3636,8 @@ map key, and the second variable, if present, is set to the corresponding
string or array element or map value. string or array element or map value.
The types of the array or slice index (always <code>int</code>) The types of the array or slice index (always <code>int</code>)
and element, or of the map key and value respectively, and element, or of the map key and value respectively,
must be <a href="#Assignment_compatibility">assignment compatible</a> to the iteration variables. must be <a href="#Assignment_compatibility">assignment compatible</a> with
the type of the iteration variables.
</p> </p>
<p> <p>
For strings, the "range" clause iterates over the Unicode code points For strings, the "range" clause iterates over the Unicode code points
@ -3798,8 +3807,9 @@ type:
<ol> <ol>
<li>The return value or values may be explicitly listed <li>The return value or values may be explicitly listed
in the "return" statement. Each expression must be single-valued in the "return" statement. Each expression must be single-valued
and <a href="#Assignment_compatibility">assignment compatible</a> to the corresponding element of and <a href="#Assignment_compatibility">assignment compatible</a>
the result type of the function. with the type of the corresponding element of the function's
result type.
<pre> <pre>
func simple_f() int { func simple_f() int {
return 2 return 2
@ -4174,10 +4184,11 @@ m := make(map[string] int, 100); # map with initial space for 100 elements
<p> <p>
Go programs are constructed by linking together <i>packages</i>. Go programs are constructed by linking together <i>packages</i>.
A package is in turn constructed from one or more source files that A package in turn is constructed from one or more source files
together provide access to a set of types, constants, functions, that together declare constants, types, variables and functions
and variables. Those elements may be <i>exported</i> and used in belonging to the package and which are accessible in all files
another package. of the same package. Those elements may be
<a href="#Exported_identifiers">exported</a> and used in another package.
</p> </p>
<h3 id="Source_file_organization">Source file organization</h3> <h3 id="Source_file_organization">Source file organization</h3>
@ -4286,31 +4297,6 @@ import _ "lib/math"
</pre> </pre>
<h3 id="Multiple-file_packages">Multiple-file packages</h3>
<p>
If a package is constructed from multiple source files,
all names declared in the package block, not just uppercase ones,
are in scope in all the files in the package.
</p>
<p>
If source file <code>math1.go</code> contains
</p>
<pre>
package math
const twoPi = 6.283185307179586
function Sin(x float) float { return ... }
</pre>
<p>
then a second file <code>math2.go</code> also in
<code>package math</code>
may refer directly to <code>Sin</code> and <code>twoPi</code>.
</p>
<h3 id="An_example_package">An example package</h3> <h3 id="An_example_package">An example package</h3>
<p> <p>