HFS: Template macros: Difference between revisions

From rejetto wiki
Jump to navigation Jump to search
(→‎Logic: pythonic and, or)
Line 40: Line 40:
; if not | A | B | C : same as ''if'', but the logic is inverted. When A is true it expands to C and vice versa.
; if not | A | B | C : same as ''if'', but the logic is inverted. When A is true it expands to C and vice versa.
; not | A : true if A is not true
; not | A : true if A is not true
; and | A | B : true if both A and B are true
; and | A | B : true if both A and B are true. In details: it works as the [http://en.wikipedia.org/wiki/Pythonic pythonic] '''and''', that is, in the ''true'' case it returns '''B''' (or the last parameter, in case you specify more than two parameters).
; or | A | B : true if any of A or B are true
; or | A | B : true if any of A or B are true. In details: it works as the [http://en.wikipedia.org/wiki/Pythonic pythonic] '''or''', that is, it returns the first ''true'' parameter (yes, it supports any number of parameters). If none of the parameters is true, then it return false.
; xor | A | B : true if A is true while B is false, or the opposite
; xor | A | B : true if A is true while B is false, or the opposite
; = | A | B : true if A is the same as B. It's case insensitive. You can use the opposite macro, true if they are different, and it's name is '''!=''' or '''<>''' (use the one you like most, there's no difference).
; = | A | B : true if A is the same as B. It's case insensitive. You can use the opposite macro, true if they are different, and it's name is '''!=''' or '''<>''' (use the one you like most, there's no difference).

Revision as of 20:53, 21 December 2007

Please note: Macros are not available in current version 2.2, but they will in 2.3, and you can experiment with it using beta versions.

How macros work

Differences with symbols

Macros are similar to symbols. They are something you type in the template and is substituted (we say expands to) with meaning content when the user watch the page.

While symbols are just a name, macros have a name and optionally parameters.

You can tell symbols by macros because symbols are surrounded by %percent% signs, macros are surrounded by {{double braces}}.

More on them

How the macro will work depends on the parameters. The same macro has a different effect when the parameter change.

The macro section will copy the content of a section of the template. But which section is specified by the parameters. So, you have one macro, section, but it will expand to any content as you change the name of the section (as parameter). Let's say {{section|style}} and it will copy the content of section [style].

Parameters

After the name of the macro you can put a character "|" (its name is pipe) and then a parameter: {{name|parameter}}. If the macro requires more parameters, like 2 or 3, you just add more pipes: {{name | parameter | another parameter | don't look at me}}.

Readability

Having macro in macro, nested, can be a mess to read. To increase readability you can

  • split the syntax over several lines, and indent.
  • add a final /macroname to know that you are closing just that macro, like {{load | something /load}}. The final /load is ignored by hfs, it's just for your convenience.

Quoting

Sometimes you don't want HFS to consider a text as part of the macros syntax. There's a way to tell HFS to leave untouched the text, and it is called quoting.

To quote a text you type {{\ followed by a space, and all the text you want. To close the quoting you type /}} .

This capability is very useful with the macro set.

Full list

With letters we are denoting parameters, and their meaning is explained immediately after.

Logic

if | A | B | C
if A is true, then it expands to B, else it expands to C. When it expands to B, C is just discarded, and the vice versa. C is optional.
How you tell A is true? A is true if it is not empty and not just a zero. So if A is "hi there!", then it is true.
if not | A | B | C
same as if, but the logic is inverted. When A is true it expands to C and vice versa.
not | A
true if A is not true
and | A | B
true if both A and B are true. In details: it works as the pythonic and, that is, in the true case it returns B (or the last parameter, in case you specify more than two parameters).
or | A | B
true if any of A or B are true. In details: it works as the pythonic or, that is, it returns the first true parameter (yes, it supports any number of parameters). If none of the parameters is true, then it return false.
xor | A | B
true if A is true while B is false, or the opposite
= | A | B
true if A is the same as B. It's case insensitive. You can use the opposite macro, true if they are different, and it's name is != or <> (use the one you like most, there's no difference).
> | A | B
true if A is greater than B. Of course you can also use the related macro <.
>= | A | B
true if A is equal or greater than B. Of course you can also use the related macro <=.
switch | A | B | C | D | E | F ...
this is rather complex for non-programmers. You can learn how a switch statement is supposed to work from Wikipedia. When you know how a switch works, then you will understand this schema that will make you understand how the parameters of this macro work
switch(A) {
  case C: return D;
  case E: return F;
  ...
}
The B is a separator string for C. Let's be clearer: if you want to specify several cases in C, all of them returning D, then you can specify them separating with B.
As you can see C and D are paired, as E and F, eventually G and H, and so on. If at the end of this list of pairs, a single unpaired parameter is found, then it is used as the else/default case, when all other pairs have failed.
Let me translated the first example of Wikipedia using the macro
{{switch|%n%|,|
  0|you typed zero|
  3,5,7|%n% is a prime number|
  4,6,8|%n% is an even number|
  2|%n% is a prime and even number|
  1,9|%n% is a perfect square|
  Only single-digit numbers are allowed
}}
for | A | B | C | D | E
repeats D by replacing variable {{^A}} with every value between B and C (they are meant to be numbers).
Optionally you can specify a step for the numbers: that is, instead of going 1-by-1, they can go 2-by-2. The optional step is specified at position D; in such case the body is moved from position D to position E.

Data getting

section | A
A is the name of the [section] you want to include. Note: till build #160 it was case sensitive.
get | A
where A is the name of a value you are interested in, like to know if an option is enabled or not.
This is a list of supported values for A:
can upload
true if in the current folder the user is allowed to upload files
can recur
true if the option Recursive listing is enabled
can archive
true if the current item in list is archivable. outside the list it refers to the current folder.
can access
true if the current item in list is accessible by the user
is new
true if the current item in list is flagged as "new"
urlvar | A
url variable. Let's say in the url you see ?sort=s and you want to know that s, just use the macro urlvar|sort.
header | A
get any value from the HTTP request header. A is the name of the header field. This is something mostly for techies. Don't fret if you don't even know what the header is.
load | A
you'll love this one. You can specify A as a file name, or as a URL. It will load and expand to it. The file or URL you specify must be accessible from the server machine. A can be C:\windows\win.ini or also http://another_hfs_in_lan/the_file_i_want.txt.
filesize | A
tells you the size in bytes of the file A. At the moment URL are not supported, only local filenames.

Data manipulation

substring | A | B | C
cut C from A to B, with B not included. Example: {{substring|(|belong|you (are) belong to us}} will be (are).
If A is not specified, C is taken from the start. If B is not specified, C is taken to the end.
cut | A | B | C
cut C from position A, for B characters. The difference with macro substring is that here you specify where to cut by numeric positions. Example: with A=2 and B=3 and C=abcdef you will get bcd because it is from character 2 and for a length of 3.
If you don't specify A, it defaults to 1. If you don't specify B, it defaults to the length of C.
If A is negative, then you are counting backward from the end of C. If B is negative, then you are considering the length of C minus the amount of B.
repeat | A | B
repeat B for A times. Example: for A=5 and B=+ the result is +++++
upper | A
returns A with all letters uppercased. Example: for A=Hello the result is HELLO
lower | A
returns A with all letters lowercased. Example: for A=Hello the result is hello
trim | A
returns A with any leading and trailing space removed
replace | A | B | C
returns C with every A replaced with B
add | A | B
returns A+B where A and B are numbers
sub | A | B
returns A-B where A and B are numbers
mul | A | B
returns A*B where A and B are numbers
div | A | B
returns A/B where A and B are numbers
mod | A | B
returns A modulo B where A and B are numbers
min | A | B ...
returns the minimum over all parameters. You can have more than 2 parameters.
max | A | B ...
returns the maximum over all parameters. You can have more than 2 parameters.
count substring | A | B
tells the number of times A is present in B

Submacros

set | A | B
to be documented
call | A | B
to be documented
inc | A | B
to be documented

see forum

Localization

!string-id
to be documented

see forum

Others

comment | A
this is just discarded. It's for your convenience, to put a comment in the template. HTML comments are readable by visitors if they use show html source in their browser. Using this macro you will have comments that will never leave your server.
length | A
if A is 5 characters length, it expands to 5.
match | A | B
it is true if the content B is matched by the mask A.
match address | A | B
just like the macro match, but the mask supports ip ranges like 10.0.0.1-10.0.0.25
random | A | B | C | ...
it expands to any of the parameters, randomly
is substring | A | B
it is true if A is contained in B
append | A | B
add B at the end of file A. This may is also useful to keep special logs.
breadcrumbs | A
builds a breadcrumbs based on the current folder path. The A is a little html template that is repeated for every piece of the path, for which 2 symbols are provided: %bread-url% and %bread-name%. The simpler example for A is: <a href ="%bread-url%">%bread-name%/</a>.

Shortcuts

$A expands to, section | A
?A expands to, urlvar | A
^A expands to, call | A
to be documented: =

Execution order

The current execution order of macros is: from inner to outer, from left to right.

An example: {A {B} {C}} {D}. In this scenario, the order is B, C, A, D. Because B and C are inner, but on the same level, so B is expanded before C.

Problem

All macros, except quoted ones, are expanded. Even if you use the macro if|A|B|C, independently by the value of A, both B and C are expanded. If A is true, C is discarded, and vice versa. This is an important point, because if you was using append inside C, the file will be written anyway.

Workaround to the problem

Since having C not executed when A is true (from the previous example) is a very worth having feature, there's a workaround. By quoting the bodies of if, you avoid them to be executed. After the if choice between B (then) and C (else), it removes the surrounding quoting markers, if any. Let's see with an example

{{if| %user% | {{append|file.txt|someone is in!}} /if}}

As we stated before, this won't do what it seems to do. Append will always be executed, because every macro is executed. The only way to stop this is to surround with quoting markers

{{if| %user% | {{\ {{append|file.txt|someone is in!}} /}} /if}}

By having quoted the append, it will only be executed if %user% is not void. This is because the if removes the quoting markers. This is a special behaviour by only few macros, others will just leave the quoting because they are supposed to stay. The special macros with such behaviour are: if, set and switch.