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| -rw-r--r-- | doc/go_spec.html | 61 |
1 files changed, 33 insertions, 28 deletions
diff --git a/doc/go_spec.html b/doc/go_spec.html index 6e69ece51..dade36704 100644 --- a/doc/go_spec.html +++ b/doc/go_spec.html @@ -188,10 +188,6 @@ The form <code>"a ... b"</code> represents the set of characters from <code>a</code> through <code>b</code> as alternatives. </p> -<p> -Where possible, recursive productions are used to express evaluation order -and operator precedence syntactically. -</p> <hr/> <h2>Source code representation</h2> @@ -621,8 +617,9 @@ uintptr smallest uint type large enough to store the uninterpreted </pre> <p> -Except for <code>byte</code>, which is an alias for <code>uint8</code>, -to avoid portability issues all numeric types are distinct. Conversions +To avoid portability issues all numeric types are distinct except +<code>byte</code>, which is an alias for <code>uint8</code>. +Conversions are required when different numeric types are mixed in an expression or assignment. For instance, <code>int32</code> and <code>int</code> are not the same type even though they may have the same size on a @@ -669,7 +666,7 @@ StringLit = string_lit { string_lit } . <p> A struct is a sequence of named elements, called fields, with various types. A struct type declares -an identifier and type for each field. Within a struct field identifiers +an identifier and type for each field. Within a struct, field identifiers must be unique and field types must be complete (§Types). </p> @@ -696,8 +693,8 @@ struct { <p> A field declared with a type but no field identifier is an <i>anonymous field</i>. Such a field type must be specified as -a type name <code>T</code> or as a pointer to a type name <code>*T</code> -and <code>T</code> itself may not be +a type name <code>T</code> or as a pointer to a type name <code>*T</code>, +and <code>T</code> itself, may not be a pointer or interface type. The unqualified type name acts as the field identifier. </p> @@ -706,8 +703,8 @@ a pointer or interface type. The unqualified type name acts as the field identif struct { T1; // the field name is T1 *T2; // the field name is T2 - P.T3; // the field name is the unqualified type name T3 - *P.T4; // the field name is the unqualified type name T4 + P.T3; // the field name is T3 + *P.T4; // the field name is T4 x, y int; } </pre> @@ -782,7 +779,7 @@ indices 0 through the <code>len(a)-1</code> (§Indexes). <p> A pointer type denotes the set of all pointers to variables of a given -type, called the ``base type'' of the pointer. +type, called the <i>base type</i> of the pointer. A pointer value may be <code>nil</code>. </p> @@ -826,7 +823,7 @@ The types of parameters and results must be complete. <p> For the last parameter only, instead of a type one may write <code>...</code> to indicate that the function may be invoked with -an arbitrary number (including zero) of additional arguments of any +zero or more additional arguments of any type. If parameters of such a function are named, the final identifier list must be a single name, that of the <code>...</code> parameter. </p> @@ -995,7 +992,8 @@ and the relationship between <code>len()</code> and <code>cap()</code> is: </pre> <p> -The value of an uninitialized slice is <code>nil</code>, and its length and capacity +The value of an uninitialized slice is <code>nil</code>. +The length and capacity of a <code>nil</code> slice are 0. A new, initialized slice value for a given element type <code>T</code> is made using the built-in function <code>make</code>, which takes a slice type and parameters specifying the length and optionally the capacity: @@ -1020,7 +1018,7 @@ produces the same slice as allocating an array and slicing it: </p> <pre> -make([capacity]T)[0 : length] +make([]T, capacity)[0 : length] </pre> @@ -1062,20 +1060,27 @@ map [string] interface {} The number of elements is called the length and is never negative. The length of a map <code>m</code> can be discovered using the built-in function <code>len(m)</code> and may change during execution. -The value of an uninitialized map is <code>nil</code> +The value of an uninitialized map is <code>nil</code>. </p> <p> Upon creation, a map is empty. Values may be added and removed during execution using special forms of assignment (§Assignments). A new, empty map value is made using the built-in function <code>make</code>, which takes the map type and an optional -capacity, an allocation hint, as arguments: +capacity hint as arguments: </p> <pre> -make(map[string] int, 100); +make(map[string] int) +make(map[string] int, 100) </pre> +<p> +The initial capacity does not bound its size: +maps grow to accommodate the number of items +stored in them. +</p> + <h3>Channel types</h3> <p> @@ -1113,7 +1118,7 @@ which takes the channel type and an optional capacity as arguments: </p> <pre> -make(chan int, 100); +make(chan int, 100) </pre> <p> @@ -1130,7 +1135,7 @@ Types may be <i>different</i>, <i>structurally equal</i> (or just <i>equal</i>), or <i>identical</i>. Go is <i>type safe</i>: different types cannot be mixed in binary operations and values cannot be assigned to variables of different -types. They can be assigned to variables of equal type. +types. Values can be assigned to variables of equal type. </p> <h3>Type equality and identity </h3> @@ -1245,7 +1250,7 @@ When assigning to a slice variable, the array is not copied but a slice comprising the entire array is created. </li> <li> -A value can be assigned to an interface variable if the dynamic +A value can be assigned to an interface variable if the static type of the value implements the interface. </li> <li> @@ -1273,8 +1278,8 @@ compared for equality or inequality using the <code>==</code> and Arrays and structs may not be compared to anything. </li> <li> -A slice value may only be compared explicitly against <code>nil</code> -and is equal to <code>nil</code> if it has been assigned the explicit +A slice value may only be compared explicitly against <code>nil</code>. +A slice value is equal to <code>nil</code> if it has been assigned the explicit value <code>nil</code> or if it is a variable (or array element, field, etc.) that has not been modified since it was created uninitialized. @@ -1294,15 +1299,15 @@ unequal if one equals <code>nil</code> and one does not. Pointer values are equal if they point to the same location. </li> <li> -Function values are equal if they point to the same function. +Function values are equal if they refer to the same function. </li> <li> -Channel and map values are equal if they were created by the same call of <code>make</code> +Channel and map values are equal if they were created by the same call to <code>make</code> (§Making slices, maps, and channels). </li> <li> -Interface values are comparison compatible if they have the same static type and -equal if they have the same dynamic type. +Interface values may be compared if they have the same static type. +They will be equal only if they have the same dynamic type and the underlying values are equal. </li> </ul> <hr/> @@ -1437,7 +1442,7 @@ CompleteType = Type . <p> If the type (CompleteType) is omitted, the constants take the individual types of the corresponding expressions, which may be -``ideal integer'' or ``ideal float'' (§Ideal number). If the type +<i>ideal integer</i> or <i>ideal float</i> (§Ideal number). If the type is present, all constants take the type specified, and the types of all the expressions must be assignment-compatible with that type. |