expression_language_map_transformer.md

ExpressionLanguageMapTransformer

Return a value computed from the first matching rule of a list of ExpressionLanguage condition / output pairs. Behaves like a switch/case based on expressions. The input is available in expressions as the data variable.

Transformer reference

• Service: CleverAge\ProcessBundle\Transformer\ExpressionLanguageMapTransformer
• Transformer code: expression_language_map

Accepted inputs

any: exposed as data in expressions.

Possible outputs

any: the evaluated output of the first rule whose condition is truthy, or the input (keep_missing), or null (ignore_missing).

Options

Code	Type	Required	Default	Description
map	array	X		Ordered list of rules, see below
ignore_missing	bool		false	If true, return null when no rule matches, instead of throwing an UnexpectedValueException
keep_missing	bool		false	If true, return the input when no rule matches (takes precedence on ignore_missing)

Each entry of map has the following options:

Code	Type	Required	Default	Description
condition	string	X		Expression using data; the rule matches if it is truthy
output	string	X		Expression using data, evaluated and returned on match

Examples

# Transformer options level
expression_language_map:
  map:
    - condition: 'data > 100'
      output: '"high"'
    - condition: 'data > 50'
      output: '"medium"'
    - condition: 'data >= 0'
      output: '"low"'
  ignore_missing: true

Notes

• Both condition and output are expressions: string literals must be quoted inside the expression ('"high"').
• Expressions are parsed once, when options are resolved, with the bundle's cleverage_process.expression_language service (which also exposes the PHP preg_match function).