Expressions

Additionally to simple strings, you can use expressions to set the value of an attribute. Expressions must be enclosed inside "(" and ")". Inside expressions, you can refer to attributes simply by their name. String constants must be enclosed inside quotes.

Example:

    <$define image:string="hugo.gif">
    <IMG SRC=(image) ALT="image">

will be converted to

    <IMG SRC="hugo.gif" ALT="image">

Operators

Unary operators

not expression: Negotiate (boolean) expression
set attribute: True, if attribute has been set (read: passed a value) within macro call.
defined attribute: True, if attribute was defined with <$macro> or <$define>
Exists(local uri): True, if document at local URI exists (bool). This can also be specified as an absolute URI.
Example: Exists("index.html"), Exists(":image/next.gif")
fExists(filename): True, if a file exists (bool). If you do not specify a full filename (including a device name), it will be relative to the source root directory.
Example: fExists("sepp:hugo/resi.hsc"), fExists("///child.txt"), fExists("include/global.hsc")
GetEnv(environment-variable): Get value of an environment variable.
Example: GetEnv("Workbench")
GetFileSize(local uri): Get size of a specific document. You can use the attribute HSC.Format.FileSize to change the appearence of the result.
Example: GetFileSize("../../download/hugo.lha"), GetFileSize(":nudes/resi.jpg")
GetGMTime(): Get current Greenwich Mean time. You can use the attribute HSC.Format.Time to change the appearence of the result.
GetTime(): Get current local time. You can use the attribute HSC.Format.Time to change the appearence of the result.

Binary operators

expression = expression: string comparison (case insensitive)
expression + expression: string concatenation

Example:

    <$define name:string="hugo">
    <$define here:string="here">

    <IMG SRC=(name+".gif") ALT=(name+" was "+here)>
    <$if (name="hugo")>
    This is hugo!
    <$else>
    Maybe it's sepp?
    </$if>
    AmigaOS version: <(GetEnv ("KickStart"))>

will be converted to

    <IMG SRC="hugo.gif" ALT="hugo was here">
    This is hugo!
    AmigaOS version: 40.63

At least on my machine.

Boolean expressions

If you pass an expression to a boolean attribute, the expression is evaluated as before. If the expression returned an empty string, the boolean attribute is interpreted as false. This will cause the attribute to be removed from the tag/macro-call.

Any none-empty string will set the attribute to true, resulting in a value equal to the name of attribute. (In html, writing ISMAP is short for ISMAP="ISMAP".)

Example:

    <IMG SRC=(name) ALT="nufin" ISMAP=(name="map.gif")>

will be converted to

    <IMG SRC="hugo.gif" ALT="nufin">

if name has been set to "hugo.gif", or to

    <IMG SRC="map.gif" ALT="nufin" ISMAP>

if name has been set to "map.gif". Note that only the second call enables the boolean attribute ISMAP, while it gets stripped for the first call.

Priorities

Important: Different to most programming languages, hsc does not support priorities for different operators. Therefor, expressions are simply processed sequentially (Programmer's lazyness rules).

But you can use nested brackets within complex expressions.