Literals
The following object types can be created and used insided templates:
strings
integers
floats
date objects
color objects
The “null” value (
None)boolean values (
TrueandFalse)lists
dictionaries
sets
Note that depending on the implementation language of the renderer additional
types might be supported, e.g. a Python renderer will probably support both
tuples and lists and anything supporting __getitem__() (or __iter__()
when the list is used in a loop) for lists, Java might support anything
implementing the List interface (or the Collection interface if the list
is used in a loop).
Objects of these types can either be passed to the template in the call to the render function, or the template can create objects of thoses types itself. The syntax for creating such a constant is very similar to Python’s syntax.
The “null” object
The “null” object can be referred to via None.
Boolean literals
The boolean constants can be referred to via True and False.
Integer literals
Integer constants can be written in decimal, hexadecimal, octal and binary:
42, 0x2a, 0o52 and 0b101010 all refer to the integer value 42.
Float literals
Float constants must contain a decimal point or an exponential specifier,
e.g. 42., 4e23.
String literals
Strings are delimited with single or double quotes and support all escape
sequences that Python supports (except \N{}). Strings constants allow
\uXXXX escaping. Examples:
"abc"and'abc';"'"and'\''are single quotes;'"'and"\""are double quotes;"\n"is a line feed and"\t"is a tab;"\x61"and"\u0061"are lowercase “a”s;
Strings can also be delimited with triple single or double quotes like in Python. These strings support embedded line feeds.
Date literals
Date objects have a year, month and day component and can be created like this:
@(2008-12-24)
Datetime literals
Datetime objects have a date and time including microseconds and can be created like this:
@(2008-12-24T12:34)@(2008-12-24T12:34:56)@(2008-12-24T12:34:56.987654)
Color literals
Color values are 8 bit red, green, blue and alpha values. Color constants can be created like this:
#fff#fff8#0063a8#0063a880
The variants with 3 or 6 hex digits will create a color object with an alpha value of 255.
Lists
Lists can be created like this:
[][1, 2, 3][None, 42, "foo", [False, True]]
* expressions can be used to expand other lists inplace, so
[1, *[2, 3], 4, *[5, 6]]
is equivalent to
[1, 2, 3, 4, 5, 6]
It is also possible to create a list with a list comprehension:
["(" + c.upper() + ")" for c in "hurz" if c < "u"]
This will create the list
["(H)", "(R)"]
The if condition is optional, i.e.
["(" + c.upper() + ")" for c in "hurz"]
will create the list
["(H)", "(U)", "(R)", "(Z)"]
Dictionaries
Dictionaries can be created like this:
{}{1: 2, 3: 4}{"foo": 17, "bar": 23}
** expressions can be used to expand other dictionaries inplace, so:
{"foo": 17, **{"bar": 23, "baz": 42}}
is equivalent to
{"foo": 17, "bar": 23, "baz": 42}
The ** expression must be a dictionary or a list of key/value pairs.
It is also possible to create a dictionary with a dictionary comprehension:
{ c.upper() : "(" + c + ")" for c in "hurz" if c < "u"}
This will create the dictionary
{ "H": "(h)", "R": "(r)"}
The if condition is optional, i.e.
{ c.upper() : "(" + c + ")" for c in "hurz"}
will create the dictionary
{ "H": "(h)", "U": "(u)", "R": "(r)", "Z": "(z)"}
Sets
Sets can be created like this:
{/}(this is the empty set){1, 2, 3}{"foo", "bar"}
The empty set can also be created with the function set:
set()
* expressions are also supported:
{1, *[2, 3], 4, *[5, 6]}
It is also possible to create a set with a set comprehension:
{c.upper() for c in "hurz" if c < "u"}
This will create the set
{"H", "R"}
The if condition is optional, i.e.
{c.upper() for c in "hurz"}
will create the dictionary
{"H", "R", "U", "Z"}
The Undefined object
The object Undefined will be returned when a nonexistent variable, a
nonexistent dictionary entry or an index that is out of range for a list/string
is accessed.