Popup Elements - "Hypertext without Surprises" M. Franz
Style Elements C. Szyperski 22 Jan 91
Table Elements C. Szyperski 22 Jan 91
(* to be released soon)
This documentation is a periodically updated collection of sections describing fully independent Write elements. Each section is divided into two subsections: A textual introduction into the functionality of the particular elements, followed by a list of supported commands. For each command, the command name, its explicit and implicit parameters are given. Potential implicit parameters are the caret, selections, and the marked viewer. Explicit parameters are described using a compact syntax explained in the tutorial Write.Guide.Txt. At the end of each section a list of required files is given.
E-mail update requests to the editor. Implementations of useful new Write elements are always welcome.
Companion documentation:
Write.Guide.Txt - Tutorial and Release Notes
WriteReport.Txt - Guide for Implementors of new Write Elements
Chart Elements
Chart Elements may be used to create bar charts. Starting from a tilde-terminated list of numbers, each preceded by a backslash, a set of rectangular elements is created. This can in turn be used to design simple bar charts with horizontal or vertical bars. Sample texts that have been created using Chart Elements are available as ChartElems.Txt and BenchCharts.Txt.
command explicit parameters implicit parameters
ChartElems.Create ("width" | "height") number selection
Starting from the most recent selection, the text is scanned until a "~" is found. All numbers prefixed with a backslash are replaced by a chart element. Everything else remains untouched.
Clock Elements
Analog clocks elements displaying the current time (whenever the machine is idle).
command explicit parameters implicit parameters
ClockElems.Insert [number] caret
Insert a clock (with radius given in pixels, default is 32, minimum is 12) at the caret position.
Error Elements
When using Write to edit programs, Error elements can be used to translate error lists produced by a compiler into special marking elements within the source text. Since elements move when editing text, it becomes possible to edit a large number of errors at a time. Error elements are temporary elements and hence vanish automatically when storing a marked Write text.
By clicking on a error element using MM, the element may be toggled between its (initial) compact form and its full form. In the full form, the element displays the corresponding error message. In order for this function to work properly, the files Syntax8.Scn.Fnt and Oberon2Errors.Text are required. The latter contains the error code/error message pairs.
command explicit parameters implicit parameters
ErrorElems.Mark ("^" | error-list) marked viewer
Takes the list of errors produced by a compiler (position, error code pairs) and inserts error marks into the marked text. If error marks were already present in that text, they are removed beforehand.
ErrorElems.Unmark marked viewer
Remove all error elements from the marked text.
ErrorElems.LocateNext marked viewer, caret (in marked viewer)
Locate the next error element starting the search at the caret position. If no caret is set in the marked viewer, the first error element is located.
Fold Elements
Fold Elements can be used to partially and hierarchically fold texts. Folding a text stretch causes its replacement by another, usually shorter or empty text stretch. Unfolding a folded stretch reveils the original text stretch while hiding its replacement. It is possible to unfold or to fold all folds existing in a text. Also, a (partially) folded text may be compiled as if it where fully unfolded using a utility module FoldComp. FoldComp also includes the functionality of ErrorElems, as defined elsewhere in this documentation, but uses a different file Oberon.Errors to translate error codes into error messages. Oberon.Errors also contains the name of the compiler to be used by FoldComp. A demonstration of FoldElems and FoldComp is available as file FoldDemo.Txt. Also, a special tool is available: FoldElems.Tool.
command explicit parameters implicit parameters
FoldElems.Insert selection
Make selection foldable by inserting an appropriate pair of opening and closing fold elements before and after the selected text stretch, respectively.
FoldElems.Expand marked viewer
Unfolds (expands) all folds contained in the marked text.
FoldElems.Collapse marked viewer
Folds (collapses) all folds contained in the marked text.
Make all fold elements in the marked text visible or invisible.
FoldElems.Search selection, marked viewer
Search for the selected text stretch in the (partially) folded marked text starting at the caret position. Does search within folded parts and opens folds if necessary to display found text stretches. If no selection is present, the last search pattern is used again. If no caret is present, the search starts at the text's beginning.
Compile the marked text containing folds. The compiler is started on the fully expanded view of the text.
FoldComp.ShowError
Show next error after the caret position. If no caret is present, the first error in the marked text is displayed.
Graphics Elements
Graphic elements support incorporation of graphs compatible with the standard Draw package into Write texts. A single command is provided by module GraphicElems in order to insert a new graphics. Using the middle mouse button, a graphics element can be "opened" for editing. As a result, a graphics viewer is opened displaying the graph. The command GraphicElems.Update in the viewer's menu can be used to propagate changes made to the graph back to the graphics element.
command explicit parameters implicit parameters
GraphicElems.Insert ("^" | "*" | name) caret (plus marked viewer, if "*" is used)
Inserts a graphics element sized to show the graph stored in graphics file "name". If an open graphics viewer is marked, the command can be used to insert all or part of a displayed graph: if a selection exists in the marked graphics viewer's graph, only the selection is copied into the graphics element.
Icon Elements
Display a small "walking sysiphus" icon. By clicking on such an icon using MM, a screen saver is started. Using an icon editor, the file IconElems.Icon may be changed or replaced to install a different animated icon.
command explicit parameters implicit parameters
IconElems.Insert caret
Inserts a new Icon Element at the caret position.
Line Elements
Line elements support horicontal or vertical lines within a Write text. A single command is provided to insert new line elements. The insertion command takes certain parameters such that line elements can be set to automatically adapt in width and height.
Inserts a line of given or automatically adopted width and height into a Write text. Width and height may be set in units of 1/10 mm. Otherwise, the width may be set to extend to the end of the current line ("auto") or to the next tabulator position ("tab"). The height may be set to equal the paragraphs line height (determined by the parc's line attribute).
Picture Elements
Picture elements support incorporation of pictures compatible with the standard Paint package into Write texts. Using the middle mouse button, a picture element can be "opened" for editing. As a result, a picture viewer is opened displaying the picture. The command PictureElems.Update in the viewer's menu can be used to propagate changes made to the picture back to the picture element.
<to be completed>
command explicit parameters implicit parameters
PictElems.Insert ("^" | name ["scaled"]) caret
Inserts a picture element sized to show the picture stored in picture file "name".
Popup Elements - "Hypertext without Surprises"
Popup elements introduce hypertext features into Write texts. They have commands associated with them which are executed when the elements are clicked. A popup element that executes a single command is also called a "button". Popup Elements are a generalization of the "button" concept found in many hypertext systems in that they present a user with a menu of choices instead of representing only a single command.
A popup element is displayed as a rectangular "button" shape floating in the text. Clicking MM while the mouse points to a button causes the menu of commands associated with the button to appear on the screen. The command that was last chosen from this menu is highlighted and offered as a default. A new command may then be chosen from the menu by moving the mouse over it. The new command becomes highlighted and is executed when the user releases the middle mouse button. At any time, the popup action may be cancelled by releasing MM while the mouse is outside of the menu box or by a click of the left mouse button.
Interclicking MR while a menu is displayed opens a menu-edit viewer. The menu may be edited freely in this viewer. Any changes are propagated instantly to the menu in question. Popup elements may be copied freely among Write documents. Their complete state, including the last command chosen (the next default) are saved to and restored from disk when the associated document is written or opened.
When a menu command is called, Oberon.Par.text is set to the text of the menu. It is therefore possible to pass parameters to menu commands simply by including them in the menu text. Oberon.Par.vwr is set to the Viewer displaying the Write document and Oberon.Par.frame to the corresponding frame.
command explicit parameters implicit parameters
PopupElems.Insert string caret
Inserts a new popup element with an initially empty menu. The menu associated with the element may be edited in a menu-edit viewer which is opened by clicking MM on the element with MR interclick. The width of the menu is automatically adjusted to accomodate the widest command, while its line spacing is adjusted automatically to accomodate the largest font in the menu.
Note: The source is available. Ed.Open PopupElems.Mod
Style Elements
Style Elements extend standard Write Parcs by adding a name and automatic conformance of equally named parcs within a Write text. For example, a parc named "heading" may be set to format a section heading. Then, all parcs with that name use and maintain the same format as changes are propagated automatically.
When copying a style parc from one text to another the behaviour of the copied parc depends on the target text. If it already contains a style with that name, the copied parc will adopt itself to that style. Otherwise, the copied parc defines a new style. Likewise, a style parc may be renamed. If it is renamed to a style that already exists in the containing text, the parc will adopt to that style, while otherwise it introduces a new style.
Some examples for style parcs follow below. Note that the Syntax8.Scn.Fnt file should be available to get nicely labled style parcs.
command explicit parameters implicit parameters
StyleElems.Insert ("^" | name | string) caret
Insert a new style parc with the given name at the caret position. A quoted string may be used to assign names consisting of multiple words.
StyleElems.Rename ("^" | name | string) selected parc
Renames the selected parc to the given name.
Table Elements
Table Elements are automatically formatted tables created from raw, unformatted data. A plain text separated by tabulator characters into columns and by carriage returns into rows can be used to define the table. Furthermore, a certain set of options may be used to modify the default formatting of the table.
Clicking on a table element using MM opens an viewer such that the table contents can be edited. Tables may contain arbitrary Write elements, including tables. However, elements incorporated into a table are frozen as is, i.e. messages broadcasted to all visible elements in a Write frame are not passed to elements nested into a table. Hence, only static elements should be inserted into tables.
Starting from a defining Write text containing arbitrary strings separated by tabulator and carriage-return characters, a table is constructed. Tabulators separate columns, carriage-returns separate rows. The separated strings form the contents of table cells. Each such string may in turn contain arbitrary Write elements and especially it may contain nested tables. The defining text is bound to a table element and can be edited by clicking on a table with the middle mouse button. In return, a standard Write viewer is opened containing an update command in its menu bar. The syntax of the defining text is as follows, table options will be defined later.
table = {option} "/table" {line}.
line = cell {TAB cell} CR.
cell = ["#" | "&"] <string of characters not containing TAB or CR>.
A string starting with a digit, a period (.), or a sign (+ or -) is considered numeric, otherwise it is considered nonnumeric. A number sign (#) prefixing a string is suppressed and enforces numerical interpretation; likewise, an ampersand (&) prefixing a string is suppressed and enforces nonnumerical interpretation. The default table formatting causes all cells in the first column to be formatted left flush. In all other columns, the default format for numeric cells is period-aligned and that for nonnumeric cells is centered. All cells in a row are by default aligned to a common base line. Also, the default format causes the table to be framed and separating lines between rows and columns to be drawn. Finally, for a table with more than two rows or two columns the first row or column separatation line is drawn using two parallel lines, respectively. Most of the default formats can be changed using the provided option set.
For table elements the printing dilemma discussed in section 1.5 needs to be reconsidered. Following the strategy developed for Write texts, a table would be recasted when printing. However, one of the primary attributes of a table are its measures, i.e. the space taken for individual cells of the table and the arrangement of the cells with respect to each other. It is not acceptable that a table gets completely redimensioned when printed. Hence, for table elements a different printing strategy has been choosen: the displayed table on the screen follows - down to the character level - the metrics of the printer fonts. The resulting screen image looks a bit distorted, however, the displayed measures correspond as closely as possible to the printed ones.
Overview of TableElems Options
command explicit parameters implicit parameters
TableElems.Insert ["^" | name] caret
Insert a table defined by the given Write text at the caret position. If no defining file is given, an empty table is inserted.
TableElems.Update (to be called from menu frame)
Take the viewer's content frame's text as defining text and update the associated table element.
(.txt)