block_height/1
Description
block_height/1 is a predicate which unifies the given term with the current block height.
Signature
block_height(?Height) is det
where:
- Height represents the current chain height at the time of the query.
Examples
Retrieve the block height of the current block
This scenario demonstrates how to retrieve the block height of the current block.
Here are the steps of the scenario:
- Given a block with the following header:
| key | value |
|---|---|
| Height | 100 |
- Given the query:
block_height(Height).
- When the query is run
- Then the answer we get is:
height: 100
gas_used: 4140
answer:
has_more: false
variables: ["Height"]
results:
- substitutions:
- variable: Height
expression: "100"
Check that the block height is greater than a certain value
This scenario demonstrates how to check that the block height is greater than 100. This predicate is useful for governance which requires a certain block height to be reached before a certain action is taken.
Here are the steps of the scenario:
- Given a block with the following header:
| key | value |
|---|---|
| Height | 101 |
- Given the query:
block_height(Height),
Height > 100.
- When the query is run
- Then the answer we get is:
height: 101
gas_used: 4141
answer:
has_more: false
variables: ["Height"]
results:
- substitutions:
- variable: Height
expression: "101"