add PascaLigo contract

src/test/contracts/FA1.2.ligo

@@ -0,0 +1,116 @@
+type tokens     is big_map (address, nat)
+type allowances is big_map (address * address, nat) (* (sender,account) -> value *)
+
+type storage is record [
+  tokens      : tokens;
+  allowances  : allowances;
+  total_amount : nat;
+]
+
+type transfer is record [
+	address_from : address;
+	address_to   : address;
+	value        : nat;
+]
+
+type approve is record [
+	spender : address;
+	value   : nat;
+]
+
+type getAllowance is record [
+	owner    : address;
+	spender  : address;
+	callback : contract (nat);
+]
+
+type getBalance is record [
+	owner    : address;
+	callback : contract (nat);
+]
+
+type getTotalSupply is record [
+	callback : contract (nat);
+]
+
+type action is
+  	Transfer       of transfer
+|	Approve        of approve
+|	GetAllowance   of getAllowance
+|	GetBalance     of getBalance
+|	GetTotalSupply of getTotalSupply
+
+function transfer (const p : transfer; const s: storage) : list (operation) * storage is block {
+   var new_allowances : allowances := Big_map.empty;
+	if Tezos.sender = p.address_from
+	then { new_allowances := s.allowances; }
+	else {
+		var authorized_value : nat := 
+		case (Big_map.find_opt ((Tezos.sender,p.address_from), s.allowances)) of
+				Some (value) -> value
+			|	None       -> 0n
+		end;
+		if (authorized_value < p.value)
+		then { failwith("Not Enough Allowance")}
+		else { new_allowances := Big_map.update ((Tezos.sender,p.address_from), (Some (abs(authorized_value - p.value))), s.allowances) }    
+	};
+	var sender_balance : nat := case (Big_map.find_opt (p.address_from, s.tokens)) of
+		Some (value) -> value
+	|	None        -> 0n
+	end;
+	var new_tokens : tokens := Big_map.empty;
+	if (sender_balance < p.value)
+	then { failwith ("Not Enough Balance")}
+	else {
+		new_tokens := Big_map.update (p.address_from, (Some (abs(sender_balance - p.value))), s.tokens);
+		var receiver_balance : nat := case (Big_map.find_opt (p.address_to, s.tokens)) of
+			Some (value) -> value
+		|	None        -> 0n
+		end;
+		new_tokens := Big_map.update (p.address_to, (Some (receiver_balance + p.value)), new_tokens);
+	}
+} with ((nil: list (operation)), s with record [tokens = new_tokens; allowances = new_allowances])
+
+function approve (const p : approve; const s : storage) : list (operation) * storage is block {
+	var previous_value : nat := case Big_map.find_opt ((p.spender, Tezos.sender), s.allowances) of
+		Some (value) -> value
+	|	None -> 0n
+	end;
+	var new_allowances : allowances := Big_map.empty;
+	if previous_value > 0n and p.value > 0n
+	then { failwith ("Unsafe Allowance Change")}
+	else {
+		new_allowances := Big_map.update ((p.spender, Tezos.sender), (Some (p.value)), s.allowances);
+	}
+} with ((nil: list (operation)), s with record [allowances = new_allowances])
+
+function getAllowance (const p : getAllowance; const s : storage) : list (operation) * storage is block {
+	var value : nat := case Big_map.find_opt ((p.owner, p.spender), s.allowances) of
+		Some (value) -> value
+	|	None -> 0n
+	end;
+	var op : operation := Tezos.transaction (value, 0mutez, p.callback);
+} with (list [op],s)
+
+function getBalance (const p : getBalance; const s : storage) : list (operation) * storage is block {
+	var value : nat := case Big_map.find_opt (p.owner, s.tokens) of
+		Some (value) -> value
+	|	None -> 0n
+	end;
+	var op : operation := Tezos.transaction (value, 0mutez, p.callback);
+} with (list [op],s)
+
+function getTotalSupply (const p : getTotalSupply; const s : storage) : list (operation) * storage is block {
+  var total : nat := s.total_amount;
+  var op : operation := Tezos.transaction (total, 0mutez, p.callback);
+} with (list [op],s)
+
+
+function main (const a : action; const s : storage) : list (operation) * storage is
+ 	case a of
+   	Transfer       (p) -> transfer (p,s)
+	|	Approve        (p) -> approve (p,s)
+	|	GetAllowance   (p) -> getAllowance (p,s)
+	|  GetBalance     (p) -> getBalance (p,s)
+	|	GetTotalSupply (p) -> getTotalSupply (p,s)
+	end;