diff options
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 39 |
1 files changed, 29 insertions, 10 deletions
@@ -53539,6 +53539,12 @@ are instantiated with parameters. Each such expression has a type constructor symbol in the operator position, from a limited, fixed vocabulary, which cannot be extended. +Some constituents of compound type syntax are expressions which evaluate to +integer values: the dimension value for array types, the size for buffers, +and the value expressions for enumeration constants are such expressions. +These expressions allow full use of \*(TL. They are evaluated without +visibility into any apparent surrounding lexical scope. + Some predefined types which are provided are in fact typedef names. For instance, the .code size-t @@ -53963,15 +53969,20 @@ type. The remaining arguments specify the enumeration constants. In the enumeration constant syntax, each occurrence of .meta sym -They must be either a keyword symbol, or a symbols for which the +They must be a bindable symbol according to the .code bindable -function returns true. The symbols may not repeat. +function. The symbols may not repeat within the same enumerated type. +Unlike in the C language, different enumerations may use the same symbols; +they are in separate spaces. If a .meta sym is given, it is associated with an integer value which is one greater than the integer value associated with the previous symbol. -If there is no previous symbol, then the value is zero. +If there is no previous symbol, then the value is zero. If the previous +symbol has been assigned the highest possible value of the FFI +.code int +type, then an error exception is thrown. If .meti >> ( sym << value ) @@ -53979,12 +53990,13 @@ is given, then .code sym is given the specified value. The .meta value -argument may be either an integer token, or a symbol. If it is an integer -token, then the value must be in range of the FFI +is an expression which must evaluate to an integer value in range of the FFI .code int -type. If a symbol is given, it must be be one of the symbols already defined -in the same enumerated type. The new symbol is given the same value as that -symbol. +type. +It is evaluated in an environment in which the previous +symbols from the same enumeration appear as variables whose binding are the +their enumeration values, making it possible to use earlier enumerations in the +definition of later enumerations. The FFI .code enum @@ -54089,6 +54101,11 @@ Since Lisp arrays and C arrays do not share the same representation, temporary buffers are automatically created and destroyed by FFI to manage the conversion. +The +.code dim +argument is an ordinary Lisp expression expanded and evaluated in the +top-level environment. It must produce a non-negative integer value. + In addition, several types are treated specially: when .meta type is one of @@ -54539,8 +54556,10 @@ and .codn buf-d , respectively. The .meta size -argument must be an integer literal, which specifies the buffer -size. Because they have a size, these types have useful get +argument is an expression which is evaluated in the top-level +environment, and must produce a non-negative integer. + +Because they have a size, these types have useful get semantics. The get semantics of |