Weave Manual

Making Weave Scripts

Although !Weave was built with Lua, you do not need Lua installed on your computer to use it. Similarly, the syntax of Weave scripts follows (mostly) the rules of Lua syntax, but you do not need to know Lua to write them. As explained in intro the general form a Weave script is a collection of definitions followed by a return statement. The value returned must be a rope. Ropes are defined recursively as being either strings or lists of ropes. Actually this is not entirely true. The value returned must be a table, whose list-part is a rope. It can also optionally have any of the following words as indices:

BODYSTYLE
CHARSET
CSS
DOCTYPE
FILE
HEADER
LANG
QUIET
TITLE

They can appear in any order, but they must appear at the top level of the tree.

BODYSTYLE It is best to use CSS for defining the style for the body tag, but if you do want your HTML to include styles in the tag itself, do this using the value assigned to BODYSTYLE.

     => { BODYSTYLE = [[width: 800px;]]; myrope; }

CHARSET The default character set is utf-8. If you want another to override this, assign its name to CHARSET.

CSS This must optionally be assigned a value which is a rope whose strings are the URLs of CSS files you want the document to use. Each one will have its own declaration in the header of the document.

  => { CSS = { "mystyle.css"; "yourstyle.css"; }; myrope; }

DOCTYPE The default DOCTYPE tag, the first word of the document, is <!DOCTYPE html> . You can override this by assigning a rope to this. You had better know what you are doing.

FILE You can override the default output name by assigning its filepath to this.

HEADER You can use this to put more stuff into the document header by assigning a rope to it.

LANG The default value of the LANG attribute in the document header is en . You can override this by assigning a string (not a rope) language code to this.

QUIET Assigning any non-nil value, apart from false , to this will suppress the confirmatory taskwindow message if compilation is successful.

TITLE This sets the value in the TITLE tag in the header. The default value is ??? .

Variable names in Weave must be composed of letters, digits and underscores and may not start with a digit. White space and newlines are only significant as separators of words. Functions are applied to comma-separated lists of arguments in parentheses. In case of a single argument the parentheses may be omitted if the argument is a literal string or a literal list - that is if the next token is one of: ", ', [[, { . Inside quoted strings certain control characters can be expressed using the escape character \ . So the two strings:

"one\ntwo\nthree"

[[
one
two
three]]

are the same.

Weave provides, beside the pseudotables TAG, MONOTAG, CLASS, the following built in functions:

LINK
OBEY$DIR
REM
TEXT
STYLE

It is convenient to write pieces of Weave code that can be re-used in many scripts in a separate file, to avoid rewriting. The function require takes as argument either the name of a file in !Weave.lib or the absolute pathname of a file and returns the value given by the file's final return statement. It is intelligent in the sense that if a file has been loaded already, no loading is done subsequently. Local variables used in such code have scope only within the file. At present only three files are provided in !Weave.lib:

Include    List    Table

Include defines a function INCLUDE that reads a file as a string.

List defines two functions: list and linkify. They can be used like this:

    local list, linkify in require "List"
    mylist = list { rope_1; .... ; rope_n }

    my_links = linkify {
    { addr_1; label_1; }
    ....................
    { addr_n; label_n; }
    }

mylist and my_links will be unordered lists. The functions can take two further arguments, the first for the attributes of the ul tag, the second for the attributes of the li tag.

Table defines a function TABLE, used like this:

    local TABLE in require "Table"
    mytable = TABLE {
      { a_11; a_12; ......... ; a_1n; };
      .................................
      { a_m1; a_m2; ......... ; a_mn; };
    }

which can take three more arguments for the attributes of the tags table, tr, td.

LINK This uses the anchor tag to make links:

       LINK "http:yoyodyne.org/news.html" "Try it now!";

produces HTML

<a href="http:yoyodyne.org/news.html>Try it now!</a>

OBEY$DIR This function takes as a string argument a relative address of a file (relative to the output HTML file) and returns its absolute address. This is useful with require.

  my_db =  require (OBEY$DIR [[dbase_file]])

REM Puts an HTML comment into the document

TEXT Text often needs cleaning up before being inserted into HTML. Top-bit-set characters need to be replaced by character entities, and so do angle-brackets and ampersands. This function, from ropes to ropes does it for you. It will also evaluate expressions that are enclosed in parentheses and prefixed by a $-sign. If the expression contains variables, x, y, ... then TEXT must be given a second argument { x = x; y = y; .... } for the evaluation to take place.

STYLE This function takes a string, puts doublequotes round it and prefixes style= . Useful for inserting inline styles into tags.