Add Motoko. (#5611)

* Add Motoko.

* Add color for Motoko.

Co-authored-by: Colin Seymour <colin@github.com>

.gitmodules

@@ -1086,6 +1086,9 @@
 [submodule "vendor/grammars/vscode-lean"]
 	path = vendor/grammars/vscode-lean
 	url = https://github.com/leanprover/vscode-lean
+[submodule "vendor/grammars/vscode-motoko"]
+	path = vendor/grammars/vscode-motoko
+	url = https://github.com/dfinity/vscode-motoko.git
 [submodule "vendor/grammars/vscode-opa"]
 	path = vendor/grammars/vscode-opa
 	url = https://github.com/tsandall/vscode-opa

grammars.yml

@@ -949,6 +949,8 @@ vendor/grammars/vscode-lean:
 - markdown.lean.codeblock
 - source.lean
 - source.lean.markdown
+vendor/grammars/vscode-motoko:
+- source.mo
 vendor/grammars/vscode-opa:
 - source.rego
 vendor/grammars/vscode-plantuml:

lib/linguist/languages.yml

@@ -3727,6 +3727,14 @@ MoonScript:
   tm_scope: source.moonscript
   ace_mode: text
   language_id: 238
+Motoko:
+  type: programming
+  color: '#fbb03b'
+  extensions:
+  - ".mo"
+  tm_scope: source.mo
+  ace_mode: text
+  language_id: 202937027
 Motorola 68K Assembly:
   type: programming
   color: "#005daa"

samples/Motoko/erc20.mo

@@ -0,0 +1,174 @@
+import HashMap "mo:base/HashMap";
+import Iter "mo:base/Iter";
+import Principal "mo:base/Principal";
+
+import Errors "errors";
+import Events "events";
+
+shared({caller}) actor class ERC20 (
+    tkName : Text,       // Name of the token.
+    tkSymbol : Text,     // Symbol of the token.
+    tkDecimals : Nat8,   // Number of decimals the token uses.
+    tkTotalSupply : Nat, // Total token supply.
+) = {
+    private stable let _name : Text = tkName;
+    // Returns the name of the token.
+    public query func name() : async Text {
+        _name;
+    };
+
+    private stable let _symbol : Text = tkSymbol;
+    // Returns the symbol of the token.
+    public query func symbol() : async Text {
+        _symbol;
+    };
+
+    private stable let _decimals : Nat8 = tkDecimals;
+    // Returns the number of decimals the token uses.
+    public query func decimals() : async Nat8 {
+        _decimals;
+    };
+
+    private stable let _totalSupply : Nat = tkTotalSupply;
+    // Returns the total token supply.
+    public query func totalSupply() : async Nat {
+        _totalSupply;
+    };
+
+    private stable var _balances : [(Principal, Nat)] = [];
+    private var balances = HashMap.HashMap<
+        Principal, // Address owner.
+        Nat,       // Amount of tokens.
+    >(0, Principal.equal, Principal.hash);
+    balances.put(caller, tkTotalSupply);
+    public query func balanceOf(owner : Principal) : async Nat {
+        _balanceOf(owner);
+    };
+    // Returns the account balance of another account with address 'owner'.
+    private func _balanceOf(owner : Principal) : Nat {
+        switch (balances.get(owner)) {
+            case (null)      { 0;       };
+            case (? balance) { balance; };
+        };
+    };
+
+    // Transfers 'value' amount of tokens to address 'to'.
+    public shared({caller}) func transfer(
+        to : Principal,                  // Recipient of the tokens.
+        value : Nat,                     // Amount of tokens.
+        transferEvent: ?Events.Transfer, // Transfer event.
+    ) : async Bool {
+        let balance = _balanceOf(caller);
+        if (balance < value) { throw Errors.InsufficientBalance(balance, value); };
+        _transfer(caller, to, value); // Transfer value.
+        ignore Events.fireTransfer(   // Fire transfer event.
+            transferEvent, caller, to, value,
+        );
+        true;
+    };
+    // @pre: account balance > value
+    private func _transfer(from : Principal, to : Principal, value : Nat) {
+        if (value == 0) { return; };
+
+        let fromBalance          = _balanceOf(from);
+        let newFromBalance : Nat = fromBalance - value;
+        if (newFromBalance == 0) { balances.delete(from);              }
+        else                     { balances.put(from, newFromBalance); };
+        let toBalance          = _balanceOf(to);
+        let newToBalance : Nat = toBalance + value;
+        balances.put(to, newToBalance);
+    };
+
+    // Transfers 'value' amount of tokens from address 'from' to address 'to'.
+    // NOTE: the caller must be approved by the owner to tranfer tokens, even if the caller is the owner.
+    public shared({caller}) func transferFrom(
+        from: Principal,                 // Owner of the tokens.
+        to : Principal,                  // Recipient of the tokens.
+        value : Nat,                     // Amount of tokens.
+        transferEvent: ?Events.Transfer, // Transfer event.
+    ) : async Bool {
+        let allowed = _allowance(from, caller);
+        if (allowed < value) { throw Errors.InsufficientAllowance(allowed, value); };
+        let balance = _balanceOf(from);
+        if (balance < value) { throw Errors.InsufficientBalance(balance, value); };
+        let newAllowed : Nat = allowed - value;
+        _approve(from, caller, newAllowed);
+        _transfer(from, to, value);
+        true;
+    };
+
+    // Allows 'spender' to withdraw from your account multiple times, up to the 'value' amount. 
+    // If this function is called again it overwrites the current allowance with 'value'.
+    public shared({caller}) func approve(
+        spender: Principal,              // Spender of the tokens.
+        value: Nat,                      // Amount of tokens.
+        approvalEvent: ?Events.Approval, // Approval event.
+    ) : async Bool {
+        _approve(caller, spender, value);
+        ignore Events.fireApproval( // Fire approval event.
+            approvalEvent, caller, spender, value,
+        );
+        true;
+    };
+    private func _approve(owner : Principal, spender: Principal, value : Nat) {
+        switch (allowances.get(owner)) {
+            case (null) {
+                if (value == 0) { return; };
+
+                let allowance = HashMap.HashMap<Principal, Nat>(1, Principal.equal, Principal.hash);
+                allowance.put(spender, value);
+                allowances.put(owner, allowance);
+            };
+            case (? allowance) {
+                if (value == 0) {
+                    // Delete if value is 0.
+                    allowance.delete(spender);
+                    if (allowance.size() == 0) {
+                        allowances.delete(owner);
+                    };
+                } else {
+                    allowance.put(spender, value);
+                    allowances.put(owner, allowance);
+                };
+            };
+        };
+    };
+
+    private stable var _allowances : [(Principal, [(Principal, Nat)])] = [];
+    private var allowances = HashMap.HashMap<
+        Principal, // Address owner.
+        HashMap.HashMap<
+            Principal, // Address spender.
+            Nat,       // Amount of tokens.
+        >,
+    >(1, Principal.equal, Principal.hash);
+    // Returns the amount which 'spender' is still allowed to withdraw from 'owner'.
+    public query func allowance(owner: Principal, spender: Principal) : async Nat {
+        _allowance(owner, spender);
+    };
+    private func _allowance(owner: Principal, spender: Principal) : Nat {
+        switch(allowances.get(owner)) {
+            case (?allowance_owner) {
+                switch(allowance_owner.get(spender)) {
+                    case (?allowance) { return allowance; };
+                    case (null)       { return 0; };
+                }
+            };
+            case (null) { return 0; };
+        }
+    };
+
+    system func preupgrade() {
+        _balances := Iter.toArray(balances.entries());
+    };
+
+    system func postupgrade() {
+        balances := HashMap.fromIter<Principal,Nat>(
+            _balances.vals(),
+            0,
+            Principal.equal,
+            Principal.hash,
+        );
+        _balances := [];
+    };
+};

samples/Motoko/queue.mo

@@ -0,0 +1,41 @@
+import List "mo:base/List";
+
+module {
+    // A simple FIFO queue.
+    public type Queue<V> = (
+        List.List<V>, // <-  in
+        List.List<V>, // out ->
+    );
+
+    // Pushes an element onto the given queue.
+    public func push<V>(v : V, (i, o) : Queue<V>) : Queue<V> = (?(v, i), o);
+
+    // Pops an element from the given queue.
+    public func pop<V>(q : Queue<V>) : (?V, Queue<V>) {
+        switch (peek(q)) {
+            case (null, _)     { (null, q);          };
+            case (? x, (i, o)) { (?x, (i, tail(o))); };
+        };
+    };
+
+    // Peeks at the top element from the given queue.
+    public func peek<V>(q : Queue<V>) : (?V, Queue<V>) {
+        switch (q) {
+            case ((null, null))  { (null, q);                      };
+            case ((xs, null))    { peek((null, List.reverse(xs))); };
+            case ((_, ?(x, xs))) { (?x, q);                        };
+        };
+    };
+
+    // Returns the size of the given queue.
+    public func size<V> ((i, o) : Queue<V>) : Nat {
+        List.size(i) + List.size(o);
+    };
+
+    private func tail<V>(l : List.List<V>) : List.List<V> {
+        switch (l) {
+            case (null)      { null; };
+            case (? (x, xs)) { xs;   };
+        };
+    };
+};

vendor/README.md

@@ -295,6 +295,7 @@ This is a list of grammars that Linguist selects to provide syntax highlighting
 - **Modula-3:** [newgrammars/m3](https://github.com/newgrammars/m3)
 - **Monkey:** [gingerbeardman/monkey.tmbundle](https://github.com/gingerbeardman/monkey.tmbundle)
 - **MoonScript:** [leafo/moonscript-tmbundle](https://github.com/leafo/moonscript-tmbundle)
+- **Motoko:** [dfinity/vscode-motoko](https://github.com/dfinity/vscode-motoko)
 - **Motorola 68K Assembly:** [zerkman/language-m68k](https://github.com/zerkman/language-m68k)
 - **Muse:** [Alhadis/language-emacs-lisp](https://github.com/Alhadis/language-emacs-lisp)
 - **Mustache:** [textmate/php-smarty.tmbundle](https://github.com/textmate/php-smarty.tmbundle)

vendor/grammars/vscode-motoko

@@ -0,0 +1 @@
+Subproject commit d16c61b175e41586dda62f9387fdea2de39992d7

vendor/licenses/git_submodule/vscode-motoko.dep.yml

@@ -0,0 +1,227 @@
+---
+name: vscode-motoko
+version: d16c61b175e41586dda62f9387fdea2de39992d7
+type: git_submodule
+homepage: https://github.com/dfinity/vscode-motoko.git
+license: apache-2.0
+licenses:
+- sources: LICENSE
+  text: |2
+
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+  text: |-
+    Copyright 2020 DFINITY Foundation
+
+    Licensed under the Apache License, Version 2.0 (the "License");
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