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Diffstat (limited to 'Doc/lib/libformatter.tex')
| -rw-r--r-- | Doc/lib/libformatter.tex | 147 |
1 files changed, 74 insertions, 73 deletions
diff --git a/Doc/lib/libformatter.tex b/Doc/lib/libformatter.tex index 94cd6d6..9ecd1cc 100644 --- a/Doc/lib/libformatter.tex +++ b/Doc/lib/libformatter.tex @@ -6,8 +6,9 @@ This module supports two interface definitions, each with mulitple implementations. The \emph{formatter} interface is used by the -\code{HTMLParser} class of the \code{htmllib} module, and the +\class{HTMLParser} class of the \module{htmllib} module, and the \emph{writer} interface is required by the formatter interface. +\withsubitem{(im module htmllib)}{\ttindex{HTMLParser}} Formatter objects transform an abstract flow of formatting events into specific output events on writer objects. Formatters manage several @@ -47,17 +48,17 @@ be called without having to track whether the property was changed. The following attributes are defined for formatter instance objects: -\setindexsubitem{(formatter object data)} +\setindexsubitem{(formatter attribute)} \begin{datadesc}{writer} The writer instance with which the formatter interacts. \end{datadesc} -\setindexsubitem{(formatter object method)} +\setindexsubitem{(formatter method)} \begin{funcdesc}{end_paragraph}{blanklines} -Close any open paragraphs and insert at least \code{blanklines} +Close any open paragraphs and insert at least \var{blanklines} before the next paragraph. \end{funcdesc} @@ -70,13 +71,13 @@ break the logical paragraph. Insert a horizontal rule in the output. A hard break is inserted if there is data in the current paragraph, but the logical paragraph is not broken. The arguments and keywords are passed on to the writer's -\code{send_line_break()} method. +\method{send_line_break()} method. \end{funcdesc} \begin{funcdesc}{add_flowing_data}{data} Provide data which should be formatted with collapsed whitespaces. Whitespace from preceeding and successive calls to -\code{add_flowing_data()} is considered as well when the whitespace +\method{add_flowing_data()} is considered as well when the whitespace collapse is performed. The data which is passed to this method is expected to be word-wrapped by the output device. Note that any word-wrapping still must be performed by the writer object due to the @@ -86,55 +87,55 @@ need to rely on device and font information. \begin{funcdesc}{add_literal_data}{data} Provide data which should be passed to the writer unchanged. Whitespace, including newline and tab characters, are considered legal -in the value of \code{data}. +in the value of \var{data}. \end{funcdesc} \begin{funcdesc}{add_label_data}{format, counter} Insert a label which should be placed to the left of the current left margin. This should be used for constructing bulleted or numbered -lists. If the \code{format} value is a string, it is interpreted as a -format specification for \code{counter}, which should be an integer. +lists. If the \var{format} value is a string, it is interpreted as a +format specification for \var{counter}, which should be an integer. The result of this formatting becomes the value of the label; if -\code{format} is not a string it is used as the label value directly. +\var{format} is not a string it is used as the label value directly. The label value is passed as the only argument to the writer's -\code{send_label_data()} method. Interpretation of non-string label +\method{send_label_data()} method. Interpretation of non-string label values is dependent on the associated writer. Format specifications are strings which, in combination with a counter value, are used to compute label values. Each character in the format string is copied to the label value, with some characters recognized to indicate a transform on the counter value. Specifically, the -character \samp{1} represents the counter value formatter as an -arabic number, the characters \samp{A} and \samp{a} represent -alphabetic representations of the counter value in upper and lower -case, respectively, and \samp{I} and \samp{i} represent the -counter value in Roman numerals, in upper and lower case. Note that -the alphabetic and roman transforms require that the counter value be -greater than zero. +character \character{1} represents the counter value formatter as an +arabic number, the characters \character{A} and \character{a} +represent alphabetic representations of the counter value in upper and +lower case, respectively, and \character{I} and \character{i} +represent the counter value in Roman numerals, in upper and lower +case. Note that the alphabetic and roman transforms require that the +counter value be greater than zero. \end{funcdesc} \begin{funcdesc}{flush_softspace}{} Send any pending whitespace buffered from a previous call to -\code{add_flowing_data()} to the associated writer object. This +\method{add_flowing_data()} to the associated writer object. This should be called before any direct manipulation of the writer object. \end{funcdesc} \begin{funcdesc}{push_alignment}{align} Push a new alignment setting onto the alignment stack. This may be -\code{AS_IS} if no change is desired. If the alignment value is -changed from the previous setting, the writer's \code{new_alignment()} -method is called with the \code{align} value. +\constant{AS_IS} if no change is desired. If the alignment value is +changed from the previous setting, the writer's \method{new_alignment()} +method is called with the \var{align} value. \end{funcdesc} \begin{funcdesc}{pop_alignment}{} Restore the previous alignment. \end{funcdesc} -\begin{funcdesc}{push_font}{(size, italic, bold, teletype)} +\begin{funcdesc}{push_font}{\code{(}size, italic, bold, teletype\code{)}} Change some or all font properties of the writer object. Properties -which are not set to \code{AS_IS} are set to the values passed in +which are not set to \constant{AS_IS} are set to the values passed in while others are maintained at their current settings. The writer's -\code{new_font()} method is called with the fully resolved font +\method{new_font()} method is called with the fully resolved font specification. \end{funcdesc} @@ -144,10 +145,10 @@ Restore the previous font. \begin{funcdesc}{push_margin}{margin} Increase the number of left margin indentations by one, associating -the logical tag \code{margin} with the new indentation. The initial +the logical tag \var{margin} with the new indentation. The initial margin level is \code{0}. Changed values of the logical tag must be -true values; false values other than \code{AS_IS} are not sufficient -to change the margin. +true values; false values other than \constant{AS_IS} are not +sufficient to change the margin. \end{funcdesc} \begin{funcdesc}{pop_margin}{} @@ -157,15 +158,15 @@ Restore the previous margin. \begin{funcdesc}{push_style}{*styles} Push any number of arbitrary style specifications. All styles are pushed onto the styles stack in order. A tuple representing the -entire stack, including \code{AS_IS} values, is passed to the writer's -\code{new_styles()} method. +entire stack, including \constant{AS_IS} values, is passed to the +writer's \method{new_styles()} method. \end{funcdesc} \begin{funcdesc}{pop_style}{\optional{n\code{ = 1}}} -Pop the last \code{n} style specifications passed to -\code{push_style()}. A tuple representing the revised stack, -including \code{AS_IS} values, is passed to the writer's -\code{new_styles()} method. +Pop the last \var{n} style specifications passed to +\method{push_style()}. A tuple representing the revised stack, +including \constant{AS_IS} values, is passed to the writer's +\method{new_styles()} method. \end{funcdesc} \begin{funcdesc}{set_spacing}{spacing} @@ -175,7 +176,7 @@ Set the spacing style for the writer. \begin{funcdesc}{assert_line_data}{\optional{flag\code{ = 1}}} Inform the formatter that data has been added to the current paragraph out-of-band. This should be used when the writer has been manipulated -directly. The optional \code{flag} argument can be set to false if +directly. The optional \var{flag} argument can be set to false if the writer manipulations produced a hard line break at the end of the output. \end{funcdesc} @@ -189,20 +190,20 @@ subclassing. \setindexsubitem{(in module formatter)} -\begin{funcdesc}{NullFormatter}{\optional{writer\code{ = None}}} -A formatter which does nothing. If \code{writer} is omitted, a -\code{NullWriter} instance is created. No methods of the writer are -called by \code{NullWriter} instances. Implementations should inherit -from this class if implementing a writer interface but don't need to -inherit any implementation. -\end{funcdesc} +\begin{classdesc}{NullFormatter}{\optional{writer}} +A formatter which does nothing. If \var{writer} is omitted, a +\class{NullWriter} instance is created. No methods of the writer are +called by \class{NullFormatter} instances. Implementations should +inherit from this class if implementing a writer interface but don't +need to inherit any implementation. +\end{classdesc} -\begin{funcdesc}{AbstractFormatter}{writer} +\begin{classdesc}{AbstractFormatter}{writer} The standard formatter. This implementation has demonstrated wide applicability to many writers, and may be used directly in most circumstances. It has been used to implement a full-featured world-wide web browser. -\end{funcdesc} +\end{classdesc} @@ -211,9 +212,9 @@ world-wide web browser. Interfaces to create writers are dependent on the specific writer class being instantiated. The interfaces described below are the required interfaces which all writers must support once initialized. -Note that while most applications can use the \code{AbstractFormatter} -class as a formatter, the writer must typically be provided by the -application. +Note that while most applications can use the +\class{AbstractFormatter} class as a formatter, the writer must +typically be provided by the application. \setindexsubitem{(writer object method)} @@ -222,40 +223,40 @@ Flush any buffered output or device control events. \end{funcdesc} \begin{funcdesc}{new_alignment}{align} -Set the alignment style. The \code{align} value can be any object, +Set the alignment style. The \var{align} value can be any object, but by convention is a string or \code{None}, where \code{None} indicates that the writer's ``preferred'' alignment should be used. -Conventional \code{align} values are \code{'left'}, \code{'center'}, +Conventional \var{align} values are \code{'left'}, \code{'center'}, \code{'right'}, and \code{'justify'}. \end{funcdesc} \begin{funcdesc}{new_font}{font} -Set the font style. The value of \code{font} will be \code{None}, +Set the font style. The value of \var{font} will be \code{None}, indicating that the device's default font should be used, or a tuple -of the form (\var{size}, \var{italic}, \var{bold}, \var{teletype}). -Size will be a string indicating the size of font that should be used; -specific strings and their interpretation must be defined by the -application. The \var{italic}, \var{bold}, and \var{teletype} values -are boolean indicators specifying which of those font attributes -should be used. +of the form \code{(}\var{size}, \var{italic}, \var{bold}, +\var{teletype}\code{)}. Size will be a string indicating the size of +font that should be used; specific strings and their interpretation +must be defined by the application. The \var{italic}, \var{bold}, and +\var{teletype} values are boolean indicators specifying which of those +font attributes should be used. \end{funcdesc} \begin{funcdesc}{new_margin}{margin, level} -Set the margin level to the integer \code{level} and the logical tag -to \code{margin}. Interpretation of the logical tag is at the +Set the margin level to the integer \var{level} and the logical tag +to \var{margin}. Interpretation of the logical tag is at the writer's discretion; the only restriction on the value of the logical tag is that it not be a false value for non-zero values of -\code{level}. +\var{level}. \end{funcdesc} \begin{funcdesc}{new_spacing}{spacing} -Set the spacing style to \code{spacing}. +Set the spacing style to \var{spacing}. \end{funcdesc} \begin{funcdesc}{new_styles}{styles} -Set additional styles. The \code{styles} value is a tuple of -arbitrary values; the value \code{AS_IS} should be ignored. The -\code{styles} tuple may be interpreted either as a set or as a stack +Set additional styles. The \var{styles} value is a tuple of +arbitrary values; the value \constant{AS_IS} should be ignored. The +\var{styles} tuple may be interpreted either as a set or as a stack depending on the requirements of the application and writer implementation. \end{funcdesc} @@ -265,8 +266,8 @@ Break the current line. \end{funcdesc} \begin{funcdesc}{send_paragraph}{blankline} -Produce a paragraph separation of at least \code{blankline} blank -lines, or the equivelent. The \code{blankline} value will be an +Produce a paragraph separation of at least \var{blankline} blank +lines, or the equivelent. The \var{blankline} value will be an integer. \end{funcdesc} @@ -274,7 +275,7 @@ integer. Display a horizontal rule on the output device. The arguments to this method are entirely application- and writer-specific, and should be interpreted with care. The method implementation may assume that a -line break has already been issued via \code{send_line_break()}. +line break has already been issued via \method{send_line_break()}. \end{funcdesc} \begin{funcdesc}{send_flowing_data}{data} @@ -290,12 +291,12 @@ for display. Generally, this should be interpreted to mean that line breaks indicated by newline characters should be preserved and no new line breaks should be introduced. The data may contain embedded newline and tab characters, unlike data provided to the -\code{send_formatted_data()} interface. +\method{send_formatted_data()} interface. \end{funcdesc} \begin{funcdesc}{send_label_data}{data} -Set \code{data} to the left of the current left margin, if possible. -The value of \code{data} is not restricted; treatment of non-string +Set \var{data} to the left of the current left margin, if possible. +The value of \var{data} is not restricted; treatment of non-string values is entirely application- and writer-dependent. This method will only be called at the beginning of a line. \end{funcdesc} @@ -305,7 +306,7 @@ will only be called at the beginning of a line. Three implementations of the writer object interface are provided as examples by this module. Most applications will need to derive new -writer classes from the \code{NullWriter} class. +writer classes from the \class{NullWriter} class. \setindexsubitem{(in module formatter)} @@ -321,10 +322,10 @@ else. Each method simply announces itself by printing its name and arguments on standard output. \end{funcdesc} -\begin{funcdesc}{DumbWriter}{\optional{file\code{ = None}\optional{\, maxcol\code{ = 72}}}} +\begin{funcdesc}{DumbWriter}{\optional{file\optional{\, maxcol\code{ = 72}}}} Simple writer class which writes output on the file object passed in -as \code{file} or, if \code{file} is omitted, on standard output. The +as \var{file} or, if \var{file} is omitted, on standard output. The output is simply word-wrapped to the number of columns specified by -\code{maxcol}. This class is suitable for reflowing a sequence of +\var{maxcol}. This class is suitable for reflowing a sequence of paragraphs. \end{funcdesc} |