Element reference syntax

Element reference syntax is used by Momotor checklets to allow recipes and config bundles to easily and consistently refer to elements of a bundle using a standardized syntax. Usually these references are used in the recipe and config bundle options.

Reference

A reference refers to one or more Result, Property, File or Option elements in bundles.

The syntax for a reference is:

typed_reference ::=  type "[" reference [ "," reference ]* "]"
type            ::=  "file" | "prop" | "opt" | "result" | outcome | not_outcome
reference       ::=  [ "@" provider ] [ "#" id ( "," id )* ] [ ":" ref ]
outcome         ::=  "pass" | "fail" | "error" | "skip"
not_outcome     ::=  "not-" outcome
provider        ::=  "recipe" | "config" | "product" | "step" | "result"
ref             ::=  name | class "#" name | name "@" domain

The type defines the element type which is referenced. Choices are

type	element referenced
prop	One or more Property elements
file	One or more File elements
opt	One or more Option elements
result	One or more Result elements
pass / fail / skip / error	All Result elements with given outcome, e.g. pass selects all passed results
not-pass / not-fail / not-skip / not-error	All Result elements with a different outcome, e.g. not-pass selects all results that did not pass

The provider selects the bundle from which these elements are referenced. Choices are

provider	element referenced
@recipe	The RecipeBundle bundle
@config	The ConfigBundle bundle
@product	The ProductBundle bundle
@result	Result elements in a RecipeBundle bundle
@step	The current Step in the RecipeBundle bundle

Not all type / provider combinations are valid. For the prop, result, outcome and not_outcome types, only the @result provider is valid. Since there is only one provider valid for these types, specifying the provider is optional in this case. For the opt and file types, all providers are valid.

Since ResultsBundle bundles contain multiple results, one or more id tokens can be specified to limit the list of results. If no id is given, all results in the bundle are referenced. id is not used with other providers. The id can contain task references, see Task ID.

The prop, file and opt types require an additional name and a class (for file types) or a domain (for opt types). For file types, the name can contain glob-like wildcards and can be quoted if it contains space or any other special characters. For opt types, if domain is not provided it defaults to checklet.

Examples of references are:

reference	result
prop[:name1]	Selects properties with name name1 from all results in the results bundle
prop[#id1:name1]	Selects properties with name name1 from result with result id #id1
prop[@result#id1:name1]	Same as above (@result is optional and implied)
file[@config:class1#name1]	Selects the file with class class1 and exact name name1 from the config
file[@config:class1#*.txt]	Selects all files with class class1 and name ending with .txt from the config
file[@recipe:class1#"doc 1.txt"]	Selects all files with class class1 and exact name doc 1.txt from the recipe
opt[@step:name1]	Selects the option with name name1 in (default) domain checklet of the current step
opt[@step:name1@domain1]	Selects the option with name name1 in domain domain1 of the current step
result	Select all results from the results bundle
result[#id1]	Select result with id id1 from the results bundle
pass	Select all passed results from the results bundle
pass[#id1,#id2]	Select results with result id id1 and id2, if they passed
pass[@result#id1,#id2]	Same as above (@result is optional and implied)
not-pass[@result#id1,#id2]	Select results with result id id1 and id2, if they did not pass

Reference value

A reference value is a single value generated from a Reference. Checklets can use reference values in options to resolve those options into values. References are also used as part of the Placeholder syntax.

A reference value is a Reference optionally prefixed with a modifier:

value_reference ::=  [ "%" mod ] typed_reference
mod             ::=  "all" | "any" | "sum" | "max" | "min" | "cat" | "join"
                     | "joinc" | "joins" | "joincs" | "json" | "first" | "last"

What value is produced by a reference is determined by the reference type:

type	value
prop / opt	The value attribute of the referenced Property or Option elements
file	The name attribute of the referenced File elements
result	The outcome attribute of the referenced Result elements 1
pass / fail / skip / error / not-pass / not-fail / not-skip / not-error	The step_id attribute of the referenced Result elements 1

1(1,2)

The result and outcome / not_outcome types produce different values, although they both reference Result elements.

The mod modifier indicates how the list of values produced by the reference is converted into a single value. The default modifier is join, but this can be changed by the caller of the resolve_value_reference() method.

mod	result
%all	True if all values are considered True 2
%any	True if at least one value is considered True 2
%notall	False if all values are considered True 2
%notany	False if at least one value is considered True 2
%not	Alias for %notany
%sum	The sum of the values 3
%max	The maximum of the values 3
%min	The minimum of the values 3
%cat	All values concatenated without any separator
%join	All values concatenated with a single comma, without spaces
%joinc	Alias for %join
%joins	All values concatenated with a space character
%joincs	All values concatenated with a comma followed by a space
%json	The values converted into a json list 4
%first	The first value 5
%last	The last value 5

2(1,2,3,4)

For the all, any, not, notall and notany the values are interpreted as booleans in the same way Python does: a 0 (zero), None or empty string is considered to be False, and anything else is considered to be True. Empty sequences result in None.

3(1,2,3)

For the sum, max and min modifiers, string values will be cast into float or int if possible, or ignored otherwise. If all values resolve to integers, the result of these modifiers will be an integer. If at least one of the values is a floating point value, the result will be a float. Empty sequences result in None.

4

The json modifier returns a json list with the values converted to equivalent JSON types.

5(1,2)

The first and last modifiers return the first or last value and keep the type intact. Empty sequences result in None.

All other modifiers convert the values to a string before joining.

Selector

A Selector filters references on the referenced value. The value is one of the attributes of the referenced elements, the same attribute as used for value references.

A selector has the following syntax:

selector    ::=  typed_reference [ selection ]
selection   ::=  unary_oper | binary_oper value
unary_oper  ::=  "?" | "!"
binary_oper ::=  "==" | "!=" | ">" | ">=" | "<" | "<="

operator	action
(no selector)	Selects all elements (i.e. same as the reference)
?	Unary operator which selects the elements whose value is considered True 6
!	Unary operator which selects the elements whose value is considered False 6
== / ~= / > / >= / < / <=	Binary operators. Selects the elements whose value matches the equation. String values to compare with need to be quoted.

6(1,2)

For the ? and ! operators the values are interpreted as booleans in the same way Python does: a 0 (zero), None or empty string is considered to be False, and anything else is considered to be True.

Example selectors:

selector
pass	Selects all passed results
result=="pass"	Also selects all passed results
prop[score]	Selects all results containing a score property
prop[score]>1	Selects all results with a score property greater than 1

Match

match ::=  [ "%" mod ] selector
mod   ::=  "all" | "any" | "not" | "notall" | "notany"

A Match takes a Selector and collapses it into a boolean, depending on the mod modifier.

mod	match
No modifier or %all	Matches if the selector is “true” for all referenced elements
%any	Matches if there is at least one selected element “true”
%notall	Matches if not all or the selected elements are “true”
%not or %notany	Matches if not any of the selected elements is “true”

elements	no modifier or %all	%any	%notall	%not %notany
all true	true	true	false	false
all false	false	false	true	true
mixed	false	true	true	false

Example matches:

match
pass	Matches if all results passed
%any pass	Matches if at least one result passed
%notall pass	Matches if not all results passed
%notany pass	Matches if at least one result did not pass
prop[score]	Matches if all results contain a score property
%any prop[score]	Matches if at least one result contains a score property
prop[score]>1	Matches if all results contain a score or more than 1

Placeholder

Placeholders can be used inside a longer string. The placeholder will be replaced by the value produced by the Reference value

placeholder ::=  "${" value_reference "}"

Placeholders are reference values wrapped inside a ${...}. To include a literal ${ in the string, use $${ to escape the placeholder syntax.