anchor.diff:  
   [source,js]
   --------------------------------------------------
  -"DECAY_FUNCTION": {
  -    "FIELD_NAME": {
  +"DECAY_FUNCTION": { <1>
  +    "FIELD_NAME": { <2>
             "origin": "11, 12",
             "scale": "2km",
             "offset": "0km",
  
positive.code: "weight" : number
  --------------------------------------------------
  
  ==== Random
  
  The `random_score` generates scores using a hash of the `_uid` field,
  
negative.code: By default, modifying the score does not change which documents match. To exclude
  documents that do not meet a certain score threshold the `min_score` parameter can be set to the desired score threshold.
  
  [[score-functions]]
  
  The `function_score` query provides several types of score functions.
  
  * <<function-script-score,`script_score`>>
  * <<function-weight,`weight`>>
  * <<function-random,`random_score`>>
  * <<function-field-value-factor,`field_value_factor`>>
  * <<function-decay,decay functions>>: `gauss`, `linear`, `exp`
  
  [[function-script-score]]
  ==== Script score
  
  The `script_score` function allows you to wrap another query and customize
  