# Kernel helpers

Here is a complete reference of Michelson kernel helpers.

NOTE

These instructions are not Michelson primitives and thus cannot be used outside of the Jupyter environment.

# DUMP

Returns the whole stack with values, types, and annotations if any.

PUSH @var nat 42 ;
DUMP

value	type	name
42	nat	@var

# DUMP n

Returns top n items from the stack.

PUSH string "1" ;
PUSH string "2" ;
PUSH string "3" ;
DUMP 2

stdout
PUSH: push 1;
PUSH: push 2;
PUSH: push 3;

value	type
"3"	string
"2"	string

# DROP_ALL

Clears the stack.

DROP_ALL ;
DUMP

stack is empty

# EXPAND { code }

Expands Michelson macros.

EXPAND { PAPAIIR }

{ { DIP { PAIR } ; PAIR } }

# PATCH prim value?

Sets value for one of the context-dependent Michelson instructions: AMOUNT, BALANCE, NOW, SOURCE, SENDER, CHAIN_ID.
You can leave second parameter empty, 0 will be used in that case.

PATCH AMOUNT 100500 ;
AMOUNT

stdout
PATCH: set AMOUNT=100500;
AMOUNT: push 100500;

value	type	name
100500	mutez	@amount

# DEBUG bool

Enables or disables verbose output.

DEBUG False ;
PUSH nat 42

value	type
42	nat

DEBUG True

# BIG_MAP_DIFF

Takes the top of the stack, searches for temporary big_map instances in that element, and displays what the big_map_diff would be like if it was a contract execution ending.

EMPTY_BIG_MAP string string ;
PUSH string "bar" ;
SOME ;
PUSH string "foo" ;
UPDATE ;
BIG_MAP_DIFF

stdout
EMPTY_BIG_MAP: push -1;
PUSH: push bar;
SOME: pop bar; push ('bar',);
PUSH: push foo;
UPDATE: pop foo, ('bar',), -1; push -1;
BIG_MAP_DIFF:

big_map	action	key	value
0	alloc	string	string
0	update	"foo"	"bar"

# BEGIN %entrypoint (param_expr) (storage_expr)

Simulates the contract execution beginning. Requires parameter and storage sections to be initialized. Also, clears the stack.
The %entrypoint argument can be omitted, %default will be used in that case.
This helper also allocates temporary big_map instances if there are any in parameters or storage types.

parameter unit ;
storage unit ;
BEGIN Unit Unit ;

stdout
parameter unit;
storage unit;
BEGIN: use %default; drop all; push (Unit, Unit);

value	type
Pair Unit Unit	pair unit unit

# COMMIT

Simulates the contract execution ending. Requires a Pair of operation list and valid storage on top of the stack.
Returns a list of internal operations, new storage, and big_map_diff.

DROP ;
UNIT ;
NIL operation ;
PAIR ;
COMMIT  ## in our case it will be just new storage

stdout
DROP: pop (Unit, Unit);
UNIT: push Unit;
NIL: push [];
PAIR: pop [], Unit; push ([], Unit);
COMMIT:

value	type
Unit	unit

# RESET network?

Clears the stack, deletes all big_map instances, initializes CHAIN_ID variable, and remembers the chosen network.
Can be used to set real network context in order to access blockchain data and typecheck values of contract type.
If network is not specified, CHAIN_ID will we unset.

PUSH address "KT18jLSuXycuWi9pL7ByRjqkrWpPF1S6maHY" ;
CONTRACT unit ;  ## no typechecking
ASSERT_SOME ;

stdout
PUSH: push KT18jLSuXycuWi9pL7ByRjqkrWpPF1S6maHY;
CONTRACT: pop KT18jLSuXycuWi9pL7ByRjqkrWpPF1S6maHY; skip check; push ('KT18jLSuXycuWi9pL7ByRjqkrWpPF1S6maHY%default',);
IF_NONE: pop ('KT18jLSuXycuWi9pL7ByRjqkrWpPF1S6maHY%default',); push KT18jLSuXycuWi9pL7ByRjqkrWpPF1S6maHY%default;
  RENAME: pop KT18jLSuXycuWi9pL7ByRjqkrWpPF1S6maHY%default; push KT18jLSuXycuWi9pL7ByRjqkrWpPF1S6maHY%default;

value	type
"KT18jLSuXycuWi9pL7ByRjqkrWpPF1S6maHY%default"	contract unit

RESET "mainnet" ;
CHAIN_ID ;
PUSH address "KT18jLSuXycuWi9pL7ByRjqkrWpPF1S6maHY" ;
CONTRACT unit ;
ASSERT_SOME ;

stdout
RESET: set NETWORK='mainnet'; set CHAIN_ID=NetXdQprcVkpaWU; drop all;
CHAIN_ID: push NetXdQprcVkpaWU;
PUSH: push KT18jLSuXycuWi9pL7ByRjqkrWpPF1S6maHY;
CONTRACT: pop KT18jLSuXycuWi9pL7ByRjqkrWpPF1S6maHY; not found; push None;
IF_NONE: pop None;
  UNIT: push Unit;
  FAILWITH: pop Unit;

stderr
MichelsonRuntimeError: Unit
at IF_NONE -> FAILWITH

RESET

# RUN %entrypoint (param_expr) (storage_expr)

Requires code section to be initialized. Internally calls BEGIN, then executes code, and finishes with COMMIT.

parameter unit ;
storage unit ;
code { CDR ; NIL operation ; PAIR }

stdout
parameter unit;
storage unit;
code { CDR ; NIL operation ; PAIR };

RUN Unit Unit

stdout
RUN: use %default; drop all; push (Unit, Unit);
  CDR: pop (Unit, Unit); push Unit;
  NIL: push [];
  PAIR: pop [], Unit; push ([], Unit);

value	type
Unit	unit

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