version 1.13, 1995/03/20 18:16:24
|
version 1.14, 1995/04/20 09:42:52
|
Line 286 that has become a de-facto standard for
|
Line 286 that has become a de-facto standard for
|
@table @var |
@table @var |
@item word |
@item word |
The name of the word. BTW, GNU Forth is case insensitive, so you can |
The name of the word. BTW, GNU Forth is case insensitive, so you can |
type the words in in lower case. |
type the words in in lower case (However, @pxref{core-idef}). |
|
|
@item Stack effect |
@item Stack effect |
The stack effect is written in the notation @code{@var{before} -- |
The stack effect is written in the notation @code{@var{before} -- |
Line 1050 poses the following questions:
|
Line 1050 poses the following questions:
|
|
|
@menu |
@menu |
* Where are locals visible by name?:: |
* Where are locals visible by name?:: |
* How long do locals live? :: |
* How long do locals live?:: |
* Programming Style:: |
* Programming Style:: |
* Implementation:: |
* Implementation:: |
@end menu |
@end menu |
Line 1487 locals wordset.
|
Line 1487 locals wordset.
|
@node Defining Words, Wordlists, Locals, Words |
@node Defining Words, Wordlists, Locals, Words |
@section Defining Words |
@section Defining Words |
|
|
|
@menu |
|
* Values:: |
|
@end menu |
|
|
@node Values, , Defining Words, Defining Words |
@node Values, , Defining Words, Defining Words |
@subsection Values |
@subsection Values |
|
|
Line 1619 doc-does-code!
|
Line 1623 doc-does-code!
|
doc-does-handler! |
doc-does-handler! |
doc-/does-handler |
doc-/does-handler |
|
|
|
|
|
|
@node ANS conformance, Model, Words, Top |
@node ANS conformance, Model, Words, Top |
@chapter ANS conformance |
@chapter ANS conformance |
|
|
|
ANS Forth systems are required to document certain implementation |
|
choices. This chapter tries to meet these requirements. In many cases it |
|
gives a way to ask the system for the information instead of providing |
|
the information directly, in particular, if the information depends on |
|
the processor, the operating system or the installation options chosen, |
|
or if they are likely to change during the maintenance of gforth. |
|
|
|
@comment The framework for the rest has been taken from pfe. |
|
|
|
@menu |
|
* The Core Words:: |
|
* The optional Block word set:: |
|
* The optional Double Number word set:: |
|
* The optional Exception word set:: |
|
* The optional Facility word set:: |
|
* The optional File-Access word set:: |
|
* The optional Floating-Point word set:: |
|
* The optional Locals word set:: |
|
* The optional Memory-Allocation word set:: |
|
* The optional Programming-Tools word set:: |
|
* The optional Search-Order word set:: |
|
* The optional String word set:: |
|
@end menu |
|
|
|
|
|
@c ===================================================================== |
|
@node The Core Words, The optional Block word set, ANS conformance, ANS conformance |
|
@comment node-name, next, previous, up |
|
@section The Core Words |
|
@c ===================================================================== |
|
|
|
@menu |
|
* core-idef:: |
|
* core-ambcond:: |
|
* core-other:: |
|
@end menu |
|
|
|
@c --------------------------------------------------------------------- |
|
@node core-idef, core-ambcond, The Core Words, The Core Words |
|
@comment node-name, next, previous, up |
|
@subsection Implementation Defined Options |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item (Cell) aligned addresses: |
|
processor-dependent. Gforths alignment words perform natural alignment |
|
(e.g., an address aligned for a datum of size 8 is divisible by |
|
8). Unaligned accesses usually result in a @code{-23 THROW}. |
|
|
|
@item @code{EMIT} and non-graphic characters: |
|
The character is output using the C library function (actually, macro) |
|
@code{putchar}. |
|
|
|
@item character editing of @code{ACCEPT} and @code{EXPECT}: |
|
This is modeled on the GNU readline library (@pxref{Readline |
|
Interaction, , Command Line Editing, readline, The GNU Readline |
|
Library}) with Emacs-like key bindings. @kbd{Tab} deviates a little by |
|
producing a full word completion every time you type it (instead of |
|
producing the common prefix of all completions). |
|
|
|
@item character set: |
|
The character set of your computer and display device. Gforth is |
|
8-bit-clean (but some other component in your system may make trouble). |
|
|
|
@item Character-aligned address requirements: |
|
installation-dependent. Currently a character is represented by a C |
|
@code{unsigned char}; in the future we might switch to @code{wchar_t} |
|
(Comments on that requested). |
|
|
|
@item character-set extensions and matching of names: |
|
Any character except 0 can be used in a name. Matching is |
|
case-insensitive. The matching is performed using the C function |
|
@code{strncasecmp}, whose function is probably influenced by the |
|
locale. E.g., the @code{C} locale does not know about accents and |
|
umlauts, so they are matched case-sensitively in that locale. For |
|
portability reasons it is best to write programs such that they work in |
|
the @code{C} locale. Then one can use libraries written by a Polish |
|
programmer (who might use words containing ISO Latin-2 encoded |
|
characters) and by a French programmer (ISO Latin-1) in the same program |
|
(of course, @code{WORDS} will produce funny results for some of the |
|
words (which ones, depends on the font you are using)). Also, the locale |
|
you prefer may not be available in other operating systems. Hopefully, |
|
Unicode will solve these problems one day. |
|
|
|
@item conditions under which control characters match a space delimiter: |
|
If @code{WORD} is called with the space character as a delimiter, all |
|
white-space characters (as identified by the C macro @code{isspace()}) |
|
are delimiters. @code{PARSE}, on the other hand, treats space like other |
|
delimiters. @code{PARSE-WORD} treats space like @code{WORD}, but behaves |
|
like @code{PARSE} otherwise. @code{(NAME)}, which is used by the outer |
|
interpreter (aka text interpreter) by default, treats all white-space |
|
characters as delimiters. |
|
|
|
@item format of the control flow stack: |
|
The data stack is used as control flow stack. The size of a control flow |
|
stack item in cells is given by the constant @code{cs-item-size}. At the |
|
time of this writing, an item consists of a (pointer to a) locals list |
|
(third), an address in the code (second), and a tag for identifying the |
|
item (TOS). The following tags are used: @code{defstart}, |
|
@code{live-orig}, @code{dead-orig}, @code{dest}, @code{do-dest}, |
|
@code{scopestart}. |
|
|
|
@item conversion of digits > 35 |
|
The characters @code{[\]^_'} are the digits with the decimal value |
|
36@minus{}41. There is no way to input many of the larger digits. |
|
|
|
@item display after input terminates in @code{ACCEPT} and @code{EXPECT}: |
|
The cursor is moved to the end of the entered string. If the input is |
|
terminated using the @kbd{Return} key, a space is typed. |
|
|
|
@item exception abort sequence of @code{ABORT"}: |
|
The error string is stored into the variable @code{"error} and a |
|
@code{-2 throw} is performed. |
|
|
|
@item input line terminator: |
|
For interactive input, @kbd{C-m} and @kbd{C-j} terminate lines. One of |
|
these characters is typically produced when you type the @kbd{Enter} or |
|
@kbd{Return} key. |
|
|
|
@item maximum size of a counted string: |
|
@code{s" /counted-string" environment? drop .}. Currently 255 characters |
|
on all ports, but this may change. |
|
|
|
@item maximum size of a parsed string: |
|
Given by the constant @code{/line}. Currently 255 characters. |
|
|
|
@item maximum size of a definition name, in characters: |
|
31 |
|
|
|
@item maximum string length for @code{ENVIRONMENT?}, in characters: |
|
31 |
|
|
|
@item method of selecting the user input device: |
|
The user input device is the standard input. There is current no way to |
|
change it from within gforth. However, the input can typically be |
|
redirected in the command line that starts gforth. |
|
|
|
@item method of selecting the user output device: |
|
The user output device is the standard output. It cannot be redirected |
|
from within gforth, but typically from the command line that starts |
|
gforth. Gforth uses buffered output, so output on a terminal does not |
|
become visible before the next newline or buffer overflow. Output on |
|
non-terminals is invisible until the buffer overflows. |
|
|
|
@item methods of dictionary compilation: |
|
Waht are we expected to document here? |
|
|
|
@item number of bits in one address unit: |
|
@code{s" address-units-bits" environment? drop .}. 8 in all current |
|
ports. |
|
|
|
@item number representation and arithmetic: |
|
Processor-dependent. Binary two's complement on all current ports. |
|
|
|
@item ranges for integer types: |
|
Installation-dependent. Make environmental queries for @code{MAX-N}, |
|
@code{MAX-U}, @code{MAX-D} and @code{MAX-UD}. The lower bounds for |
|
unsigned (and positive) types is 0. The lower bound for signed types on |
|
two's complement and one's complement machines machines can be computed |
|
by adding 1 to the upper bound. |
|
|
|
@item read-only data space regions: |
|
The whole Forth data space is writable. |
|
|
|
@item size of buffer at @code{WORD}: |
|
@code{PAD HERE - .}. 104 characters on 32-bit machines. The buffer is |
|
shared with the pictured numeric output string. If overwriting |
|
@code{PAD} is acceptable, it is as large as the remaining dictionary |
|
space, although only as much can be sensibly used as fits in a counted |
|
string. |
|
|
|
@item size of one cell in address units: |
|
@code{1 cells .}. |
|
|
|
@item size of one character in address units: |
|
@code{1 chars .}. 1 on all current ports. |
|
|
|
@item size of the keyboard terminal buffer: |
|
Varies. You can determine the size at a specific time using @code{lp@ |
|
tib - .}. It is shared with the locals stack and TIBs of files that |
|
include the current file. You can change the amount of space for TIBs |
|
and locals stack at gforth startup with the command line option |
|
@code{-l}. |
|
|
|
@item size of the pictured numeric output buffer: |
|
@code{PAD HERE - .}. 104 characters on 32-bit machines. The buffer is |
|
shared with @code{WORD}. |
|
|
|
@item size of the scratch area returned by @code{PAD}: |
|
The remainder of dictionary space. You can even use the unused part of |
|
the data stack space. The current size can be computed with @code{sp@ |
|
pad - .}. |
|
|
|
@item system case-sensitivity characteristics: |
|
Dictionary searches are case insensitive. However, as explained above |
|
under @i{character-set extensions}, the matching for non-ASCII |
|
characters is determined by the locale you are using. In the default |
|
@code{C} locale all non-ASCII characters are matched case-sensitively. |
|
|
|
@item system prompt: |
|
@code{ ok} in interpret state, @code{ compiled} in compile state. |
|
|
|
@item division rounding: |
|
installation dependent. @code{s" floored" environment? drop .}. We leave |
|
the choice to gcc (what to use for @code{/}) and to you (whether to use |
|
@code{fm/mod}, @code{sm/rem} or simply @code{/}). |
|
|
|
@item values of @code{STATE} when true: |
|
-1. |
|
|
|
@item values returned after arithmetic overflow: |
|
On two's complement machines, arithmetic is performed modulo |
|
2**bits-per-cell for single arithmetic and 4**bits-per-cell for double |
|
arithmetic (with appropriate mapping for signed types). Division by zero |
|
typically results in a @code{-55 throw} (floatingpoint unidentified |
|
fault), although a @code{-10 throw} (divide by zero) would be more |
|
appropriate. |
|
|
|
@item whether the current definition can be found after @t{DOES>}: |
|
No. |
|
|
|
@end table |
|
|
|
@c --------------------------------------------------------------------- |
|
@node core-ambcond, core-other, core-idef, The Core Words |
|
@comment node-name, next, previous, up |
|
@subsection Ambiguous conditions |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item a name is neither a word nor a number: |
|
@code{-13 throw} (Undefined word) |
|
|
|
@item a definition name exceeds the maximum length allowed: |
|
@code{-19 throw} (Word name too long) |
|
|
|
@item addressing a region not inside the various data spaces of the forth system: |
|
The stacks, code space and name space are accessible. Machine code space is |
|
typically readable. Accessing other addresses gives results dependent on |
|
the operating system. On decent systems: @code{-9 throw} (Invalid memory |
|
address). |
|
|
|
@item argument type incompatible with parameter: |
|
This is usually not caught. Some words perform checks, e.g., the control |
|
flow words, and issue a @code{ABORT"} or @code{-12 THROW} (Argument type |
|
mismatch). |
|
|
|
@item attempting to obtain the execution token of a word with undefined execution semantics: |
|
You get an execution token representing the compilation semantics |
|
instead. |
|
|
|
@item dividing by zero: |
|
typically results in a @code{-55 throw} (floating point unidentified |
|
fault), although a @code{-10 throw} (divide by zero) would be more |
|
appropriate. |
|
|
|
@item insufficient data stack or return stack space: |
|
Not checked. This typically results in mysterious illegal memory |
|
accesses, producing @code{-9 throw} (Invalid memory address) or |
|
@code{-23 throw} (Address alignment exception). |
|
|
|
@item insufficient space for loop control parameters: |
|
like other return stack overflows. |
|
|
|
@item insufficient space in the dictionary: |
|
Not checked. Similar results as stack overflows. However, typically the |
|
error appears at a different place when one inserts or removes code. |
|
|
|
@item interpreting a word with undefined interpretation semantics: |
|
For some words, we defined interpretation semantics. For the others: |
|
@code{-14 throw} (Interpreting a compile-only word). Note that this is |
|
checked only by the outer (aka text) interpreter; if the word is |
|
@code{execute}d in some other way, it will typically perform it's |
|
compilation semantics even in interpret state. (We could change @code{'} |
|
and relatives not to give the xt of such words, but we think that would |
|
be too restrictive). |
|
|
|
@item modifying the contents of the input buffer or a string literal: |
|
These are located in writable memory and can be modified. |
|
|
|
@item overflow of the pictured numeric output string: |
|
Not checked. |
|
|
|
@item parsed string overflow: |
|
@code{PARSE} cannot overflow. @code{WORD} does not check for overflow. |
|
|
|
@item producing a result out of range: |
|
On two's complement machines, arithmetic is performed modulo |
|
2**bits-per-cell for single arithmetic and 4**bits-per-cell for double |
|
arithmetic (with appropriate mapping for signed types). Division by zero |
|
typically results in a @code{-55 throw} (floatingpoint unidentified |
|
fault), although a @code{-10 throw} (divide by zero) would be more |
|
appropriate. @code{convert} and @code{>number} currently overflow |
|
silently. |
|
|
|
@item reading from an empty data or return stack: |
|
The data stack is checked by the outer (aka text) interpreter after |
|
every word executed. If it has underflowed, a @code{-4 throw} (Stack |
|
underflow) is performed. Apart from that, the stacks are not checked and |
|
underflows can result in similar behaviour as overflows (of adjacent |
|
stacks). |
|
|
|
@item unexepected end of the input buffer, resulting in an attempt to use a zero-length string as a name: |
|
@code{Create} and its descendants perform a @code{-16 throw} (Attempt to |
|
use zero-length string as a name). Words like @code{'} probably will not |
|
find what they search. Note that it is possible to create zero-length |
|
names with @code{nextname} (should it not?). |
|
|
|
@item @code{>IN} greater than input buffer: |
|
The next invocation of a parsing word returns a string wih length 0. |
|
|
|
@item @code{RECURSE} appears after @code{DOES>}: |
|
Compiles a recursive call to the defining word not to the defined word. |
|
|
|
@item argument input source different than current input source for @code{RESTORE-INPUT}: |
|
!!???If the argument input source is a valid input source then it gets |
|
restored. Otherwise causes @code{-12 THROW} which unless caught issues |
|
the message "argument type mismatch" and aborts. |
|
|
|
@item data space containing definitions gets de-allocated: |
|
Deallocation with @code{allot} is not checked. This typically resuls in |
|
memory access faults or execution of illegal instructions. |
|
|
|
@item data space read/write with incorrect alignment: |
|
Processor-dependent. Typically results in a @code{-23 throw} (Address |
|
alignment exception). Under Linux on a 486 or later processor with |
|
alignment turned on, incorrect alignment results in a @code{-9 throw} |
|
(Invalid memory address). There are reportedly some processors with |
|
alignment restrictions that do not report them. |
|
|
|
@item data space pointer not properly aligned, @code{,}, @code{C,}: |
|
Like other alignment errors. |
|
|
|
@item less than u+2 stack items (@code{PICK} and @code{ROLL}): |
|
Not checked. May cause an illegal memory access. |
|
|
|
@item loop control parameters not available: |
|
Not checked. The counted loop words simply assume that the top of return |
|
stack items are loop control parameters and behave accordingly. |
|
|
|
@item most recent definition does not have a name (@code{IMMEDIATE}): |
|
@code{abort" last word was headerless"}. |
|
|
|
@item name not defined by @code{VALUE} used by @code{TO}: |
|
@code{-32 throw} (Invalid name argument) |
|
|
|
@item name not found (@code{'}, @code{POSTPONE}, @code{[']}, @code{[COMPILE]}: |
|
@code{-13 throw} (Undefined word) |
|
|
|
@item parameters are not of the same type (@code{DO}, @code{?DO}, @code{WITHIN}): |
|
Gforth behaves as if they were of the same type. I.e., you can predict |
|
the behaviour by interpreting all parameters as, e.g., signed. |
|
|
|
@item @code{POSTPONE} or @code{[COMPILE]} applied to @code{TO}: |
|
Assume @code{: X POSTPONE TO ; IMMEDIATE}. @code{X} is equivalent to |
|
@code{TO}. |
|
|
|
@item String longer than a counted string returned by @code{WORD}: |
|
Not checked. The string will be ok, but the count will, of course, |
|
contain only the least significant bits of the length. |
|
|
|
@item u greater than or equal to the number of bits in a cell (@code{LSHIFT}, @code{RSHIFT}: |
|
Processor-dependent. Typical behaviours are returning 0 and using only |
|
the low bits of the shift count. |
|
|
|
@item word not defined via @code{CREATE}: |
|
@code{>BODY} produces the PFA of the word no matter how it was defined. |
|
|
|
@code{DOES>} changes the execution semantics of the last defined word no |
|
matter how it was defined. E.g., @code{CONSTANT DOES>} is equivalent to |
|
@code{CREATE , DOES>}. |
|
|
|
@item words improperly used outside @code{<#} and @code{#>}: |
|
Not checked. As usual, you can expect memory faults. |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node core-other, , core-ambcond, The Core Words |
|
@comment node-name, next, previous, up |
|
@subsection Other system documentation |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item nonstandard words using @code{PAD}: |
|
None. |
|
|
|
@item operator's terminal facilities available: |
|
!!?? |
|
|
|
@item program data space available: |
|
@code{sp@ here - .} gives the space remaining for dictionary and data |
|
stack together. |
|
|
|
@item return stack space available: |
|
!!?? |
|
|
|
@item stack space available: |
|
@code{sp@ here - .} gives the space remaining for dictionary and data |
|
stack together. |
|
|
|
@item system dictionary space required, in address units: |
|
Type @code{here forthstart - .} after startup. At the time of this |
|
writing, this gives 70108 (bytes) on a 32-bit system. |
|
@end table |
|
|
|
|
|
@c ===================================================================== |
|
@node The optional Block word set, The optional Double Number word set, The Core Words, ANS conformance |
|
@comment node-name, next, previous, up |
|
@section The optional Block word set |
|
@c ===================================================================== |
|
|
|
@menu |
|
* block-idef:: |
|
* block-ambcond:: |
|
* block-other:: |
|
@end menu |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node block-idef, block-ambcond, The optional Block word set, The optional Block word set |
|
@comment node-name, next, previous, up |
|
@subsection Implementation Defined Options |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item the format for display by @code{LIST}: |
|
First the screen number is displayed, then 16 lines of 64 characters, |
|
each line preceded by the line number. |
|
|
|
@item the length of a line affected by @code{\}: |
|
64 characters. |
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node block-ambcond, block-other, block-idef, The optional Block word set |
|
@comment node-name, next, previous, up |
|
@subsection Ambiguous conditions |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item correct block read was not possible: |
|
Typically results in a @code{throw} of some OS-derived value (between |
|
-512 and -2048). If the blocks file was just not long enough, blanks are |
|
supplied for the missing portion. |
|
|
|
@item I/O exception in block transfer: |
|
Typically results in a @code{throw} of some OS-derived value (between |
|
-512 and -2048). |
|
|
|
@item invalid block number: |
|
@code{-35 throw} (Invalid block number) |
|
|
|
@item a program directly alters the contents of @code{BLK}: |
|
The input stream is switched to that other block, at the same |
|
position. If the storing to @code{BLK} happens when interpreting |
|
non-block input, the system will get quite confused when the block ends. |
|
|
|
@item no current block buffer for @code{UPDATE}: |
|
@code{UPDATE} has no effect. |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node block-other, , block-ambcond, The optional Block word set |
|
@comment node-name, next, previous, up |
|
@subsection Other system documentation |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item any restrictions a multiprogramming system places on the use of buffer addresses: |
|
No restrictions (yet). |
|
|
|
@item the number of blocks available for source and data: |
|
depends on your disk space. |
|
|
|
@end table |
|
|
|
|
|
@c ===================================================================== |
|
@node The optional Double Number word set, The optional Exception word set, The optional Block word set, ANS conformance |
|
@comment node-name, next, previous, up |
|
@section The optional Double Number word set |
|
@c ===================================================================== |
|
|
|
@menu |
|
* double-idef:: |
|
* double-ambcond:: |
|
* double-other:: |
|
@end menu |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node double-idef, double-ambcond, The optional Double Number word set, The optional Double Number word set |
|
@comment node-name, next, previous, up |
|
@subsection Implementation Defined Options |
|
@c --------------------------------------------------------------------- |
|
|
|
No additional documentation requirements. |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node double-ambcond, double-other, double-idef, The optional Double Number word set |
|
@comment node-name, next, previous, up |
|
@subsection Ambiguous conditions |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item @var{d} outside of range on @var{n} in @code{D>S}: |
|
The least significant cell of @var{d} is produced. |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node double-other, , double-ambcond, The optional Double Number word set |
|
@comment node-name, next, previous, up |
|
@subsection Other system documentation |
|
@c --------------------------------------------------------------------- |
|
|
|
No additional documentation requirements. |
|
|
|
|
|
@c ===================================================================== |
|
@node The optional Exception word set, The optional Facility word set, The optional Double Number word set, ANS conformance |
|
@comment node-name, next, previous, up |
|
@section The optional Exception word set |
|
@c ===================================================================== |
|
|
|
@menu |
|
* exception-idef:: |
|
* exception-ambcond:: |
|
* exception-other:: |
|
@end menu |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node exception-idef, exception-ambcond, The optional Exception word set, The optional Exception word set |
|
@comment node-name, next, previous, up |
|
@subsection Implementation Defined Options |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
@item @code{THROW}-codes used in the system: |
|
The codes -256@minus{}-511 are used for reporting signals (see |
|
@file{errore.fs}). The codes -512@minus{}-2047 are used for OS errors |
|
(for file and memory allocation operations). The mapping from OS error |
|
numbers to throw code is -512@minus{}@var{errno}. One side effect of |
|
this mapping is that undefined OS errors produce a message with a |
|
strange number; e.g., @code{-1000 THROW} results in @code{Unknown error |
|
488} on my system. |
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node exception-ambcond, exception-other, exception-idef, The optional Exception word set |
|
@comment node-name, next, previous, up |
|
@subsection Ambiguous conditions |
|
@c --------------------------------------------------------------------- |
|
|
|
No additional documentation requirements. |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node exception-other, , exception-ambcond, The optional Exception word set |
|
@comment node-name, next, previous, up |
|
@subsection Other system documentation |
|
@c --------------------------------------------------------------------- |
|
|
|
No additional documentation requirements. |
|
|
|
|
|
@c ===================================================================== |
|
@node The optional Facility word set, The optional File-Access word set, The optional Exception word set, ANS conformance |
|
@comment node-name, next, previous, up |
|
@section The optional Facility word set |
|
@c ===================================================================== |
|
|
|
@menu |
|
* facility-idef:: |
|
* facility-ambcond:: |
|
* facility-other:: |
|
@end menu |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node facility-idef, facility-ambcond, The optional Facility word set, The optional Facility word set |
|
@comment node-name, next, previous, up |
|
@subsection Implementation Defined Options |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item encoding of keyboard events (@code{EKEY}): |
|
Not yet implemeted. |
|
|
|
@item duration of a system clock tick |
|
System dependent. With respect to @code{MS}, the time is specified in |
|
microseconds. How well the OS and the hardware implement this, is |
|
another question. |
|
|
|
@item repeatability to be expected from the execution of @code{MS}: |
|
System dependent. On Unix, a lot depends on load. If the system is |
|
lightly loaded, and the delay is short enough that gforth does not get |
|
swapped out, the performance should be acceptable. Under MS-DOS and |
|
other single-tasking systems, it should be good. |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node facility-ambcond, facility-other, facility-idef, The optional Facility word set |
|
@comment node-name, next, previous, up |
|
@subsection Ambiguous conditions |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item @code{AT-XY} can't be performed on user output device: |
|
Largely terminal dependant. No range checks are done on the arguments. |
|
No errors are reported. You may see some garbage appearing, you may see |
|
simply nothing happen. |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node facility-other, , facility-ambcond, The optional Facility word set |
|
@comment node-name, next, previous, up |
|
@subsection Other system documentation |
|
@c --------------------------------------------------------------------- |
|
|
|
No additional documentation requirements. |
|
|
|
|
|
@c ===================================================================== |
|
@node The optional File-Access word set, The optional Floating-Point word set, The optional Facility word set, ANS conformance |
|
@comment node-name, next, previous, up |
|
@section The optional File-Access word set |
|
@c ===================================================================== |
|
|
|
@menu |
|
* file-idef:: |
|
* file-ambcond:: |
|
* file-other:: |
|
@end menu |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node file-idef, file-ambcond, The optional File-Access word set, The optional File-Access word set |
|
@comment node-name, next, previous, up |
|
@subsection Implementation Defined Options |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item File access methods used: |
|
@code{R/O}, @code{R/W} and @code{BIN} work as you would |
|
expect. @code{W/O} translates into the C file opening mode @code{w} (or |
|
@code{wb}): The file is cleared, if it exists, and created, if it does |
|
not (both with @code{open-file} and @code{create-file}. Under Unix |
|
@code{create-file} creates a file with 666 permissions modified by your |
|
umask. |
|
|
|
@item file exceptions: |
|
The file words do not raise exceptions (except, perhaps, memory access |
|
faults when you pass illegal addresses or file-ids). |
|
|
|
@item file line terminator: |
|
System-dependent. Gforth uses C's newline character as line |
|
terminator. What the actual character code(s) of this are is |
|
system-dependent. |
|
|
|
@item file name format |
|
System dependent. Gforth just uses the file name format of your OS. |
|
|
|
@item information returned by @code{FILE-STATUS}: |
|
@code{FILE-STATUS} returns the most powerful file access mode allowed |
|
for the file: Either @code{R/O}, @code{W/O} or @code{R/W}. If the file |
|
cannot be accessed, @code{R/O BIN} is returned. @code{BIN} is applicable |
|
along with the retured mode. |
|
|
|
@item input file state after an exception when including source: |
|
All files that are left via the exception are closed. |
|
|
|
@item @var{ior} values and meaning: |
|
The @var{ior}s returned by the file words are intended as throw |
|
codes. They typically are in the range -512@minus{}-2047 of OS errors. |
|
The mapping from OS error numbers to @var{ior}s is |
|
-512@minus{}@var{errno}. |
|
|
|
@item maximum depth of file input nesting: |
|
limited by the amount of return stack, locals/TIB stack, and the number |
|
of open files available. This should not give you troubles. |
|
|
|
@item maximum size of input line: |
|
@code{/line}. Currently 255. |
|
|
|
@item methods of mapping block ranges to files: |
|
Currently, the block words automatically access the file |
|
@file{blocks.fb} in the currend working directory. More sophisticated |
|
methods could be implemented if there is demand (and a volunteer). |
|
|
|
@item number of string buffers provided by @code{S"}: |
|
1 |
|
|
|
@item size of string buffer used by @code{S"}: |
|
@code{/line}. currently 255. |
|
|
|
@end table |
|
|
|
@c --------------------------------------------------------------------- |
|
@node file-ambcond, file-other, file-idef, The optional File-Access word set |
|
@comment node-name, next, previous, up |
|
@subsection Ambiguous conditions |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item attempting to position a file outside it's boundaries: |
|
@code{REPOSITION-FILE} is performed as usual: Afterwards, |
|
@code{FILE-POSITION} returns the value given to @code{REPOSITION-FILE}. |
|
|
|
@item attempting to read from file positions not yet written: |
|
End-of-file, i.e., zero characters are read and no error is reported. |
|
|
|
@item @var{file-id} is invalid (@code{INCLUDE-FILE}): |
|
An appropriate exception may be thrown, but a memory fault or other |
|
problem is more probable. |
|
|
|
@item I/O exception reading or closing @var{file-id} (@code{include-file}, @code{included}): |
|
The @var{ior} produced by the operation, that discovered the problem, is |
|
thrown. |
|
|
|
@item named file cannot be opened (@code{included}): |
|
The @var{ior} produced by @code{open-file} is thrown. |
|
|
|
@item requesting an unmapped block number: |
|
There are no unmapped legal block numbers. On some operating systems, |
|
writing a block with a large number may overflow the file system and |
|
have an error message as consequence. |
|
|
|
@item using @code{source-id} when @code{blk} is non-zero: |
|
@code{source-id} performs its function. Typically it will give the id of |
|
the source which loaded the block. (Better ideas?) |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node file-other, , file-ambcond, The optional File-Access word set |
|
@comment node-name, next, previous, up |
|
@subsection Other system documentation |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c ===================================================================== |
|
@node The optional Floating-Point word set, The optional Locals word set, The optional File-Access word set, ANS conformance |
|
@comment node-name, next, previous, up |
|
@section |
|
@c ===================================================================== |
|
|
|
@menu |
|
* floating-idef:: floating-ambcond:: floating-other:: |
|
* floating-ambcond:: |
|
* floating-other:: |
|
@end menu |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node floating-idef, floating-ambcond, The optional Floating-Point word set, The optional Floating-Point word set |
|
@comment node-name, next, previous, up |
|
@subsection Implementation Defined Options |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node floating-ambcond, floating-other, floating-idef, The optional Floating-Point word set |
|
@comment node-name, next, previous, up |
|
@subsection Ambiguous conditions |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node floating-other, , floating-ambcond, The optional Floating-Point word set |
|
@comment node-name, next, previous, up |
|
@subsection Other system documentation |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c ===================================================================== |
|
@node The optional Locals word set, The optional Memory-Allocation word set, The optional Floating-Point word set, ANS conformance |
|
@comment node-name, next, previous, up |
|
@section |
|
@c ===================================================================== |
|
|
|
@menu |
|
* locals-idef:: |
|
* locals-ambcond:: |
|
* locals-other:: |
|
@end menu |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node locals-idef, locals-ambcond, The optional Locals word set, The optional Locals word set |
|
@comment node-name, next, previous, up |
|
@subsection Implementation Defined Options |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node locals-ambcond, locals-other, locals-idef, The optional Locals word set |
|
@comment node-name, next, previous, up |
|
@subsection Ambiguous conditions |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node locals-other, , locals-ambcond, The optional Locals word set |
|
@comment node-name, next, previous, up |
|
@subsection Other system documentation |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c ===================================================================== |
|
@node The optional Memory-Allocation word set, The optional Programming-Tools word set, The optional Locals word set, ANS conformance |
|
@comment node-name, next, previous, up |
|
@section |
|
@c ===================================================================== |
|
|
|
@menu |
|
* memory-idef:: |
|
* memory-ambcond:: |
|
* memory-other:: |
|
@end menu |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node memory-idef, memory-ambcond, The optional Memory-Allocation word set, The optional Memory-Allocation word set |
|
@comment node-name, next, previous, up |
|
@subsection Implementation Defined Options |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node memory-ambcond, memory-other, memory-idef, The optional Memory-Allocation word set |
|
@comment node-name, next, previous, up |
|
@subsection Ambiguous conditions |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node memory-other, , memory-ambcond, The optional Memory-Allocation word set |
|
@comment node-name, next, previous, up |
|
@subsection Other system documentation |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c ===================================================================== |
|
@node The optional Programming-Tools word set, The optional Search-Order word set, The optional Memory-Allocation word set, ANS conformance |
|
@comment node-name, next, previous, up |
|
@section |
|
@c ===================================================================== |
|
|
|
@menu |
|
* programming-idef:: |
|
* programming-ambcond:: |
|
* programming-other:: |
|
@end menu |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node programming-idef, programming-ambcond, The optional Programming-Tools word set, The optional Programming-Tools word set |
|
@comment node-name, next, previous, up |
|
@subsection Implementation Defined Options |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node programming-ambcond, programming-other, programming-idef, The optional Programming-Tools word set |
|
@comment node-name, next, previous, up |
|
@subsection Ambiguous conditions |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node programming-other, , programming-ambcond, The optional Programming-Tools word set |
|
@comment node-name, next, previous, up |
|
@subsection Other system documentation |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c ===================================================================== |
|
@node The optional Search-Order word set, The optional String word set, The optional Programming-Tools word set, ANS conformance |
|
@comment node-name, next, previous, up |
|
@section |
|
@c ===================================================================== |
|
|
|
@menu |
|
* search-idef:: |
|
* search-ambcond:: |
|
* search-other:: |
|
@end menu |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node search-idef, search-ambcond, The optional Search-Order word set, The optional Search-Order word set |
|
@comment node-name, next, previous, up |
|
@subsection Implementation Defined Options |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node search-ambcond, search-other, search-idef, The optional Search-Order word set |
|
@comment node-name, next, previous, up |
|
@subsection Ambiguous conditions |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node search-other, , search-ambcond, The optional Search-Order word set |
|
@comment node-name, next, previous, up |
|
@subsection Other system documentation |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c ===================================================================== |
|
@node The optional String word set, , The optional Search-Order word set, ANS conformance |
|
@comment node-name, next, previous, up |
|
@section |
|
@c ===================================================================== |
|
|
|
@menu |
|
* string-idef:: |
|
* string-ambcond:: |
|
* string-other:: |
|
@end menu |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node string-idef, string-ambcond, The optional String word set, The optional String word set |
|
@comment node-name, next, previous, up |
|
@subsection Implementation Defined Options |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node string-ambcond, string-other, string-idef, The optional String word set |
|
@comment node-name, next, previous, up |
|
@subsection Ambiguous conditions |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
@c --------------------------------------------------------------------- |
|
@node string-other, , string-ambcond, The optional String word set |
|
@comment node-name, next, previous, up |
|
@subsection Other system documentation |
|
@c --------------------------------------------------------------------- |
|
|
|
@table @i |
|
|
|
@item |
|
|
|
@end table |
|
|
|
|
|
|