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transpec(file format) transpec(file format)
Name
transpec - translation specification for instant
Synopsis
file.ts
Description
The transpec file is used by the instant program to translate an SGML
document instance to a format suitable for a formatting application.
The convention is to name the file with the suffix .ts.
A transpec file is composed of a number of individual translation
specs. Each translation spec (transpec) is made up of a number of
fields, one per line. Translation specs are separated by a line with a
leading dash. Text after the dash is ignored. Fields are composed of
two parts, a name and a value, separated by a colon. The colon must
immediately follow the name, and any amount of whitespace (blanks and
tabs) may be present between the colon and value. Values should not be
quoted, and you should be careful of trailing spaces. (Trailing space
will be considered part of the value.) Quotes, if they appear, will be
considered part of the value of the fields. Lines that begin with
whitespace (blanks and tabs) are a continuation of the previous line;
the leading space is ignored. These characteristics are very similar
to those of e-mail headers. Lines beginning with a # (number sign) are
comments and blank lines are ignored.
Field Descriptions
Some fields are for identifying criteria that determines if a
particular spec matches an element in the instance. Others specify
what action is to take place when a match happens, such as sending text
to the output stream.
Criteria fields
Criteria fields restrict the conditions under which a single
translation spec will apply. If each field specified in a particular
transpec matches an element under consideration in the document
instance, then that translation spec is said to match. The appropriate
actions, as specified in that spec, are then taken. The program,
instant, searches the list of transpecs in the order given in the file.
Therefore, the more restrictive specs (those with more criteria) should
appear before less restrictive ones.
For quick reference, this is a brief summary of the possible criteria
fields for translation. A complete discussion of each follows.
Field Label Field Value Description
GI gi ... name of this GI
AttValue attname reg-expr current element has attribute with value
Content reg-expr is reg-expr in char content>
Context context element context, up the tree
NthChild number current element is Nth child of its parent
PAttSet attname (val) parent has this attribute set (optional to value val)
Relation relationship gi gi has relationship to current element
VarREValue var REvalue variable is set to regular expression value
VarValue var value variable is set to value
GI: gi [...]
gi is the name of the generic identifier, or element name, to
consider. More than one GI may appear in this field.
AttValue: attname regular-expression
This is an attribute name-value pair, where attname is an
attribute if the GI. The regular-expression is of the form
accepted by the unix program egrep. This pair is compared to
the corresponding attribute name-value pairs of the GI under
consideration. To simply test if an attribute us set, use . (a
dot) for regular-expression. There may be more than one of
these lines for each transpec.
Content: regular-expression
This specifies that the character content of GI contains a
string matching the regular-expression.
Context: context
This specifies the context in which to apply this translation
spec. It is either a list of generic identifiers or a regular
expression describing a list of generic identifiers, looking up
the hierarchy. The first is the parent of the GI.
NthChild: number
This specifies that the GI is the numberth child element of its
parent. Children are numbered starting with 1. Negative
numbers may be used to indicate order counting backwards. For
example, -1 denotes the last child.
PAttSet: attname
This specifies that the parent has this attribute, attname, set
to any value (not IMPLIED). A value to match may optionally be
specified after attname.
Relation: relationship gi
This specifies that the current element has the relationship to
the named gi. The acceptable relationships are: ancestor
(anywhere up the tree), child (immediate child), descendant
(anywhere down the tree), parent (immediate ancestor), sibling
(share same parent element), sibling+ (any later sibling),
sibling+1 (the immediately following sibling), sibling- (any
earlier sibling), sibling-1 (the immediately following sibling).
VarREValue: varname REvalue
This specifies that the global variable varname has the value
REvalue, where REvalue is a regular expression (see the VarValue
statement).
VarValue: varname value
This specifies that the global variable varname has the
(literal) value value (see the VarREValue statement).
There are two special GIs. If specified, _Start and _End are processed
as if they were GIs in the instance at the start and end of the
translation, respectively. Their criteria are never checked. Only
their actions are performed.
Action fields
For quick reference, this is a brief summary of the action fields for
translation. They are only performed if all the criteria are satisfied.
A complete discussion of each follows.
Field Label Field Value Description
Action spec-id use transpec whose spec ID is `spec-id'
EndText text text for end of element
Increment name increment variable `name'
Ignore key flag for ignoring element's children and/or data
Message text text to send to stderr
Quit text print text and quit program
Replace text replace this subtree with text
Set name value set variable name to value
SpecID spec-id unique Spec ID (int) of this spec
StartText text text for start of element
Action: spec-id
Use the actions of the spec identified by the SpecID with
matching identifier spec-id.
EndText: text
This specifies text to be output when the end tag is processed.
Ignore: key
This specifies that the data or children for this element are to
be ignored. Set key to all to ignore the element (data and
child elements), to data to ignore the immediate character data
content (child elements are still descended into), and to
children to process the immediate character data content but not
descended into child elements. Other actions specified in this
transpec are still performed, however.
Increment: name
This is used to increment a variable whose value is a number.
If the variable is not a number, no action will be taken. The
variable must have been previously defined. This action is done
immediately before EndText. There may be more than one of these
lines for each transpec.
Message: text
This specifies a string to be printed to the standard error when
the matching element is processed. It is intended for informing
the user of the progress of the translation. It is also used
for validation of instances (see the -v flag of instant(1)); a
spec would be written to recognize a construct that is not
allowed. This action is done immediately after StartText.
Messages are also useful for debugging spec files; one is able
to easily tell when a matching spec is processed, without
looking at the actual output of the translation. Note that the
spec writer is responsible for putting newlines (\n) in the
message text.
Replace: text
This specifies text to replace the current subtree with. This
is equivalent to StartText and Ignore.
Quit: text
This specifies text to be printed to the standard error. The
program then terminates with exit status 1. This is intended
for bailing out when an undesirable instance is encountered
(such as when it is known that the formatting application can
never handle a class of components, like tables).
Set: name value
This is used to set a variable whose name is name and value is
value. Names that would be valid for GIs in the document
instance are valid for variable names. value is the rest of the
line and may be any string. This action is done immediately
before EndText. There may be more than one of these lines for
each transpec. See the discussion on variables below.
SpecID: spec-id
This names the spec with the number spec-id. Other specs may
refer to this one by this number by an Action field or an
_action special variable. This is used for cases where several
specs to perform the exact same action.
StartText: text
This specifies text to be output when the start tag is
processed.
Other Fields
These fields may appear anywhere. The action occurs when the
translation spec file is read, before any elements are translated.
Theses are independent of any element processing.
Var: name value
This is used to define a variable whose name is name and value
is value. It is similar to Set, but it may occur anywhere in
the file and takes effect when the spec file is read.
Text Strings
The text referred to in the StartText, EndText, Replace, and Message
actions is more than simple character strings. Special sequences allow
more complex output.
One type of special sequence is for C-style string processing. Most
special characters are escaped with a \ (backslash). Like in C or shell
programs, to print a \ (backslash), you must escape it with another
backslash. These special character strings are:
\n (backslash-n)
This specifies that a newline character is to be printed to the
output stream.
\r (backslash-r)
This specifies that a carriage return character is to be printed
to the output stream.
\t (backslash-t)
This specifies that a tab character is to be printed to the
output stream.
\s (backslash-s)
This specifies that a space is to be printed to the output
stream. This is useful for the end of a transpec line, where it
can be difficult to tell if a blank is present at the end.
\007 (backslash-007)
This specifies that the character whose octal value is 007 is to
be printed to the output stream. This works for any octal
character value.
^ (caret)
This specifies the that position in the string will be at the
start of a line in the output stream.
If the first token of the text string is #include, then the second
token is taken to be a file name and that file is included. If the
file is not found, the library directory, as mentioned above, is
searched. If the text string starts with a ! (exclamation point), the
rest of the line is taken to be a command and the output of that
command is inserted.
An element's attributes may also be used in the text of output fields.
To use an attribute value, precede its name with a ${ (dollar sign-left
curly bracket) and follow it with a } (right curly bracket). (This
style is followed by the Bourne shell.) For example, ${TYPE}. If the
attribute is not set (not IMPLIED), nothing will be printed to the
output stream. To specify a value to use if the attribute is not set,
place the value after the attribute name, separated by a space. To
return the attribute value in lower-case, add a colon followed by
lower-case l (${TYPE:l}.
Variables
Variables in instant are similar to those in many other string-oriented
programming languages, such as sh and awk. They are set by: Var: name
value and Set: name value. Values may be set and reset to any string.
In a Var line, if the value begins with a !, then the rest of the line
is executed as a command, and its output is taken as the value.
A reference to the value of a variable follows the same syntax as a
reference to the value of an attribute: ${name}. If that variable has
not been defined, a null value will be returned. A default value can
be returned instead of null for an undefined variable by using the
form: ${name default}.
Variables may be used as attributes are, that is in any of the text
strings mentioned above. In fact, if an attribute name is referred to
and it is not set for a given element, instant looks for a variable
with the same name. This way global defaults can be set. If you want
to be sure that you are accessing a local variable value, not an
attribute value, you can use lower or mixed case names. Attribute
names, as passed by sgmls, are in upper case.
Any number of Var actions may appear in the spec file. These set the
values of the variables before any translation takes place. The Set
actions within transpecs are performed when that spec is processed when
an element matches the given criteria.
Preset Variables
Several variables are preset by instant upon start of the program.
Their values may be overridden in transpec files or on the command
line.
date This is the date and time that the program started. The format
is: Tue 10 Aug 1993, 16:52.
host This is the name of the host where the program is run. It is
what is returned by the gethostname library call.
transpec
This is the translation spec filename.
user This is the login name of the user running the program.
Special Variables
There is a collection of special variables called special variables.
These are identified by starting the names with a _ (underscore). This
is a summary of the special variables. A complete discussion of each
special variable follows. spec-id refers to a number specified in a
SpecID field. When used in a special variable, it means to perform the
action in that translation spec.
Note that when a spec-id is given in a special variable, the default is
to perform the translation spec named by the spec-id ignoring of any
criteria statements found there. For most special variables that use a
spec-id, postpending a "t" to the spec-id (with no spaces between them,
eg, "${_followrel child TITLE 15t}"), will cause the criteria
statements in the named translation spec to evaluate successfully
before that translation spec will be processed.
Variable Usage Description
_action spec-id do spec with id spec-id
_allatts print all attribute/value pairs
_attval att [value] spec-id use spec-id if attribute matches
_chasetogi gi spec-id follow IDREFs until gi found
_eachatt att spec-id [spec-id] do spec-id for each word of attribute value
_eachcon spec-id [spec-id] do spec-id for each word of content
_env env-variable return value of env variable
_filename filename of notation
_find rel gi spec-id find gi based on relationship
_followlink [attname] spec-id follow IDREFs [attname] and use spec-id
_followrel rel gi spec-id [spec-id] do spec-id on rel if it matches
_gi [M|L|U] return GI name; M, L, U case
_id id [spec-id] find element with ID and use spec-id
_include filename insert file here
_infile [line] instance filename [and line number]
_insertnode S|E spec-id do spec-id when element is traversed
_isset var [value] spec-id do spec-id if variable matches
_location print location of current element
_namelist spec-id [spec-id] content is namelist, do spec-id for each
_nchild [gi] number of child elements [named attname]
_osftable format [flag] print table format specification
_path print path to current element
_pattr attname value of parent's attribute
_pfind args ... same as _find, but start at parent
_relation rel gi spec-id [spec-id] do spec-id if relation matches
_set var value set variable to value
_!command command to run
_action spec-id
Use the actions of the spec identified by the SpecID with
matching identifier spec-id. This behaves similarly to the
Action action, but is in addition to the present translation
spec.
_allatts
Print all attribute name-value pairs of the current element to
the output stream. The name and value are separated by a =
(equals sign), and the value is surrounded by quotes. This can
be useful for creating a normalized version of the instance.
_attval attname [value] spec-id
If the current element has an attribute named attname,
optionally whose value matches value, use the actions of the
transpec identified by spec-id.
_chasetogi gi spec-id
Follow IDREF attributes until if finds an element whose GI is gi
or which has a child element with that GI. It will apply the
transpec spec-id to that element. By default, instant assumes
the attributes named LINKEND, LINKENDS, and IDREF are of type
IDREF or IDREFS. (This corresponds with the OSF DTDs.) You can
change this by setting the variable link_atts to a space-
separated list of attribute names.
_eachatt att spec-id [spec-id2]
The transpec named by spec-id is invoked once per each word
found in the value of the attribute att. Inside the target
transpec, the current word being processed is available in the
variable named each_A (${each_A}). If spec-id2 is specified, it
will use spec-id for the first word in the attribute and spec-
id2 for the others.
_eachcon spec-id [spec-id2]
The transpec named by spec-id is invoked once per each word
found in the content of the current element. Inside the target
transpec, the current word being processed is available in the
variable named each_C (${each_C}). If spec-id2 is specified, it
will use spec-id for the first word in the content and spec-id2
for the others.
_env env-variable
Print the value of the environment variable env-variable to the
output stream.
_filename
Print the filename of the notation associated with this element,
if any. This is used to get the filename of an external
notation entity reference. For example, to print the filename
in the latex macro from the epsf macro package, use
\\epsfboxi{${_filename}}.
_find [top] relationship args ... spec-id
Descend the document hierarchy finding elements that match one
of several criteria. When one is found, the action specified by
spec-id is performed. If top is specified, the search starts at
the top of the document hierarchy, rather than at the current
element. The possible values for relationship are gi, gi-
parent, parent, and attr, and take different arguments.
Explanations may be best done by example: _find gi CHAPTER 123
means to find elements whose GI is CHAPTER, and perform action
123; _find gi-parent TITLE CHAPTER 124 means to find elements
whose GI is TITLE and whose parent is CHAPTER, and perform
action 124; _find parent BODY 125 means to find elements whose
parent's GI is BODY, and perform action 125; _find attr TYPE
UGLY 125 means to find elements whose attribute named TYPE is
set to UGLY, and perform action 126.
_followlink [attname] spec-id
When processing an element, instant will follow the IDREF
attributes until an element with no IDREF attributes is found.
It will then apply the transpec specified by spec-id to that
element. If specified, it will follow the link pointed to by
attname. By default, instant assumes the attributes named
LINKEND and LINKENDS are if type IDREF or IDREFS. You can
change this by setting the variable link_atts to a space-
separated list of attribute names.
_followrel relationship gi spec-id [spec-id2]
If the gi has the specified relationship to the current element,
perform the action specified by spec-id on the related element.
If the relationship to gi does not exist, and spec-id2 is
present, perform spec-id2 on the current element. See the
discussion of the criteria field Relation for acceptable
relationship names.
_gi [M|L|U]
Print the name of the current GI to the output stream. If
specified, M, L, or U will ensure the GI name is printed in
mixed, lower, or upper case, respectively.
_id id [spec-id]
Find the element with id and use spec-id, if set. If not set,
use the spec for that element's context.
_include filename
Insert the file filename into the output stream.
_infile [line]
Print the name of the sgml instance file to the output stream.
If line is specified, also print the line number. This depends
on sgmls being called with the -l option.
_insertnode S|E spec-id
Do spec-id when the current element is traversed at a later
pass. This can be considered inserting a node, without content,
into the hierarchy. This is only useful if done to elements
before they are processed. Typically _chasetogi or _followlink
is specified early in an instance's processing, so that when the
elements found by one of these actions are processed in their
turn, the added actions are performed. _insertnode would be
specified as the action of a spec-id pointed to in a _chasetogi
or _followlink usage.
_location
The location of the current element is printed to the output
stream in several ways: the path to the element (see _path), a
position hint, which is the nearest title, the line number, if
the ESIS (output from sgmls) contains line numbers, and the ID
of the element, if it has one. This is especially useful when
using the Message action to validate an instance.
_namelist spec-id [spec-id2]
This assumes that the content of the current element is a
namelist (a list of element IDs), and applies the action based
on spec-id for each element pointed to. If spec-id2 is
specified, it will use spec-id for the first ID in the namelist
and spec-id2 for the others.
_nchild [gi]
Print the number of child elements of the element to the output
stream. If gi is specified, print the number of child element
with that name.
_osftable tex|tbl|check [flag]
Print table markup into the output stream. The format depends
on whether tex or tbl is specified. The flag may be one of
cellstart, cellend, rowstart, rowend, top, or bottom. The value
determines what markup or text will be generated. If cellstart
is specified, the correct markup for the beginning of a cell is
output. If top, bottom, or rowend are specified, the correct
markup for the end of the appropriate position is printed to the
output stream. If check is specified, the attributes and child
elements are checked for errors and consistency.
_path Print the path to current GI to the output stream. A path is
each element, going down the tree from the topmost element. A
number in parentheses after each element name shows which child
element the next one is in the order of children for that
element. Ordering starts at 0. For example: OSF-BOOK(3)
BODY(0) CHAPTER(4) SECTION. This says the path is <OSF-BOOK>'s
third child, <BODY>'s zeroth, and <CHAPTER>'s fourth, which is
named <SECTION>.
_pattr name
Print the value of parent's attribute whose name is name to the
output stream.
_pfind rel gi spec-id
This is exactly the same as _find except that the search starts
at the current element's parent.
_relation relationship gi spec-id [spec-id2]
If the gi has the specified relationship to the current element,
perform the action specified by spec-id on the current element.
If the relationship test fails and spec-id2 is specified,
perform that action. See the discussion of the criteria field
Relation for acceptable relationship names.
_set varname value
Set the value of the variable varname to value.
_isset varname [value] spec-id
If the value of the variable varname is set to value, then
perform action referred to by spec-id. If value is not
specified, action will be performed if varname is set to any
value.
_! command
Run the command command, directing its standard output into the
output stream.
Immediate Variables
Immediate variables are like special variables, except that they are
expanded when the transpec is originally processed (special variables
are processed later, near when the final output is being generated).
The general syntax of immediate variables is
${+immediate_variable ...}.
There is currently only one immediate variable defined:
+content
This special variable is replaced by the data content of the
current element.
Examples
The following will output the given string for elements whose generic
identifier is P (for paragraph). At the start of processing this
element, the program ensures that the output starts on a new line, the
troff macro <.P> is output, then a newline. At the end of this element
processing, the program ensures that the output starts on a new line.
GI: P
StartText: ^.P^
EndText: ^
-
The following will output the given string for elements whose generic
identifier is CMD-ARGUMENT and which have an attribute PRESENCE set to
the value OPTIONAL.
GI: CMD-ARGUMENT
AttValue: PRESENCE OPTIONAL
StartText: $\\[
EndText: $\\]
-
The following prints the section number, title, and page number of the
target of a cross reference. Assume the cross reference points to a
section element, which contains a title element. The criteria for this
spec to match is that the attribute OSFROLE is set to the value
getfull. The action is to replace the content of the <XREF> element
with the given string. When processing the string, instant will follow
the IDREF attributes of <XREF> until an element with no IDREF
attributes is found. It will then apply the transpec numbered 87 to
that element, which will print the name of the GI in mixed case into
the output stream. It will then print the LaTeX reference instruction
with the value of the LINKEND attribute as an argument. (This will
become the section number after processing by LaTeX.) It will then
follow IDREFs until if finds an element whose GI is TITLE or which has
a child element with that GI. It will apply the transpec numbered 1 to
that element, which copies the title into the output stream where the
cross reference occurs. Finally, it will print the word page followed
by the LaTeX instruction to obtain the page number of a reference.
GI: XREF
AttValue: OSFROLE getfull
Replace: ${_followlink 87} \\ref{${LINKEND}},\s
{\\bf ${_chasetogi TITLE 1}}, page \\pageref{${LINKEND}}
-
# Print GI name, in mixed case
GI: _pr_gi_name
SpecID: 87
Ignore: 1
EndText: ${_gi M}
-
GI: _pass-text
SpecID: 1
-
Related Information
instant(1), sgmls(1), egrep(1).
transpec(file format)