Gas_monad (mavryk-protocol-001-PtAtLas.Mavryk_raw_protocol_001_PtAtLas.Gas

type ('a, 'trace) t

This monad combines:

a state monad where the state is the context
two levels of error monad to distinguish gas exhaustion from other errors

It is useful for backtracking on type checking errors without backtracking the consumed gas.

type ('a, 'trace) gas_monad = ('a, 'trace) t

Alias of ('a, 'trace) t to avoid confusion when the module is open

val return : 'a -> ('a, 'trace) t

return x returns a value in the gas-monad.

val map : ('a -> 'b) -> ('a, 'trace) t -> ('b, 'trace) t

map f m maps over successful results of m using f.

val bind : ('a, 'trace) t -> ('a -> ('b, 'trace) t) -> ('b, 'trace) t

bind m f binds successful results of m and feeds it to f.

val bind_recover : 
  ('a, 'trace) t ->
  (('a, 'trace) Mavryk_protocol_environment_001_PtAtLas.Pervasives.result ->
    ('b, 'trace') t) ->
  ('b, 'trace') t

bind_recover m f binds the result of m and feeds it to f. It's another variant of bind that allows recovery from inner errors.

val of_result : 
  ('a, 'trace) Mavryk_protocol_environment_001_PtAtLas.Pervasives.result ->
  ('a, 'trace) t

of_result r is a gas-free embedding of the result r into the gas monad.

val consume_gas : Alpha_context.Gas.cost -> (unit, 'trace) t

consume_gas c consumes c amounts of gas. It's a wrapper around Gas.consume. If that fails, the whole computation within the gas-monad returns an error. See the Alpha_context.Gas module for details.

val run : 
  Alpha_context.context ->
  ('a, 'trace) t ->
  (('a, 'trace) Mavryk_protocol_environment_001_PtAtLas.Pervasives.result
   * Alpha_context.context)
    Mavryk_protocol_environment_001_PtAtLas.Error_monad.tzresult

run ctxt m runs m using the given context and returns the result along with the new context with updated gas. If the given context has unlimited mode enabled, through Gas.set_unlimited, no gas is consumed.

val record_trace_eval : 
  error_details:('error_context, 'error_trace) Script_tc_errors.error_details ->
  ('error_context -> Mavryk_protocol_environment_001_PtAtLas.Error_monad.error) ->
  ('a, 'error_trace) t ->
  ('a, 'error_trace) t

record_trace_level ~error_details f m returns a new gas-monad value that when run, records trace levels using f. This function has no effect in the case of a gas-exhaustion error or if error_details is Fast.

val fail : 'trace -> ('a, 'trace) t

fail e is return (Error e) .

module Syntax : sig ... end

Syntax module for the Gas_monad. This is intended to be opened locally in functions. Within the scope of this module, the code can include binding operators, leading to a let-style syntax. Similar to Lwt_result_syntax and other syntax modules.