roboto.templating.substitution#

Module Contents#

class roboto.templating.substitution.MappingResolver(values)#

A VariableResolver backed by a flat name -> value mapping.

Values are coerced to str on access; a missing key or a None value resolves to None (leaving the placeholder unexpanded).

Parameters:

values (Mapping[str, Any])

resolve(name)#
Parameters:

name (str)

Return type:

Optional[str]

roboto.templating.substitution.PLACEHOLDER_RE#

Recognizes {{name}} placeholders. Names start with a letter or underscore; dots are allowed so dotted names ({{dataset.id}}, {{action.name}}) work as a namespace convention for entity-bound expansion by a VariableResolver. The engine treats the full dotted string as one opaque key — the resolver decides what, if anything, it expands to.

roboto.templating.substitution.VARIABLE_NAME_RE#

Mirrors PLACEHOLDER_RE so every declared variable name is referenceable by {{name}}.

class roboto.templating.substitution.VariableResolver#

Bases: Protocol

Decides what each {{name}} placeholder expands to during substitution.

Implementations bind placeholders to a source of values — a flat mapping for agent launch, or a lazily-hydrated event namespace for triggers — keeping the substitution engine itself agnostic to where values come from.

resolve(name)#

Return the substitution string for placeholder name, or None.

Parameters:

name (str) – The placeholder name written between {{ and }}, dots included (e.g. dataset.id).

Returns:

The string to splice in, or None to leave the literal {{name}} in place.

Return type:

Optional[str]

roboto.templating.substitution.collect_placeholders(node)#

Return every {{name}} placeholder found in the string leaves of node.

node is the JSON form of a template (nested dicts, lists, scalars). Only string values are scanned; placeholder syntax in dict keys is rejected so a templated key can’t silently collapse two entries into one.

Raises:

ValueError – A dict key contains {{...}} placeholder syntax.

Parameters:

node (Any)

Return type:

set[str]

roboto.templating.substitution.substitute(node, resolver)#

Return a copy of node with each {{name}} in a string leaf expanded via resolver.

Embedded and repeated placeholders within one string are supported. A name the resolver returns None for is left as the literal {{name}}; callers that require full resolution validate the placeholder set up front with collect_placeholders().

Parameters:
Return type:

Any

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