feat: official documentation (gnolang#1046)

## Description

This PR introduces the official Gno documentation, which will be hosted
at `docs.gno.land`, using the Docusaurus framework.

As discussed with @moul, the docs are supposed to be framework agnostic,
with Docusaurus living in the `misc/docusaurus` directory.

This documentation also includes work done by @alexiscolin, @leohhhn,
@waymobetta, @harry-hov, and the Onbloc team (@dongwon8247 and @r3v4s,
migrated from their Developer Portal).
Thank you to everyone who contributed and got us to this point, for the
v1 of the docs 🙏

@leohhhn @waymobetta (and DevRels reading this in the future), full
ownership of the documentation will be relinquished to you after this PR
is merged out.

To run the docs locally:
- `cd misc/docusaurus`
- `yarn install`
- `yarn start`

<details><summary>Contributors' checklist...</summary>

- [x] Added new tests, or not needed, or not feasible
- [x] Provided an example (e.g. screenshot) to aid review or the PR is
self-explanatory
- [x] Updated the official documentation or not needed
- [x] No breaking changes were made, or a `BREAKING CHANGE: xxx` message
was included in the description
- [ ] Added references to related issues and PRs
- [ ] Provided any useful hints for running manual tests
- [ ] Added new benchmarks to [generated
graphs](https://gnoland.github.io/benchmarks), if any. More info
[here](https://github.com/gnolang/gno/blob/master/.benchmarks/README.md).
</details>

---------

Co-authored-by: jon roethke <[email protected]>
Co-authored-by: Blake <[email protected]>
Co-authored-by: Dongwon <[email protected]>
Co-authored-by: Leon Hudak <[email protected]>
Co-authored-by: Hariom Verma <[email protected]>
Co-authored-by: Alexis Colin <[email protected]>
Co-authored-by: Manfred Touron <[email protected]>
Co-authored-by: Morgan <[email protected]>

.github/CODEOWNERS

@@ -37,3 +37,6 @@ PHILOSOPHY.md                @jaekwon @moul
 CONTRIBUTING.md              @jaekwon @moul
 LICENSE.md                   @jaekwon @moul
 .github/CODEOWNERS           @jaekwon @moul
+
+# Documentation.
+docs/*                       @gnolang/devrels

docs/assets/explanation/packages/pkg-1.gno

@@ -0,0 +1,6 @@
+func TotalSupply() uint64
+func BalanceOf(account std.Address) uint64
+func Transfer(to std.Address, amount uint64)
+func Approve(spender std.Address, amount uint64)
+func TransferFrom(from, to std.Address, amount uint64)
+func Allowance(owner, spender std.Address) uint64

docs/assets/explanation/packages/pkg-2.gno

@@ -0,0 +1,11 @@
+// functions that work similarly to those of grc20
+func BalanceOf(owner std.Address) (uint64, error)
+func Approve(approved std.Address, tid TokenID) error
+func TransferFrom(from, to std.Address, tid TokenID) error
+
+// functions unique to grc721
+func OwnerOf(tid TokenID) (std.Address, error)
+func SafeTransferFrom(from, to std.Address, tid TokenID) error
+func SetApprovalForAll(operator std.Address, approved bool) error
+func GetApproved(tid TokenID) (std.Address, error)
+func IsApprovedForAll(owner, operator std.Address) bool

docs/assets/explanation/packages/pkg-3.gno

@@ -0,0 +1,12 @@
+func TestAddress(name string) std.Address {
+	if len(name) > std.RawAddressSize {
+		panic("address name cannot be greater than std.AddressSize bytes")
+	}
+	addr := std.RawAddress{}
+	// TODO: use strings.RepeatString or similar.
+	// NOTE: I miss python's "".Join().
+	blanks := "____________________"
+	copy(addr[:], []byte(blanks))
+	copy(addr[:], []byte(name))
+	return std.Address(std.EncodeBech32("g", addr))
+}

docs/assets/explanation/packages/pkg-4.gno

@@ -0,0 +1,8 @@
+admin := users.AddressOrName("g1tntwtvzrkt2gex69f0pttan0fp05zmeg5yykv8")
+test2 := users.AddressOrName(testutils.TestAddress("test2"))
+recv := users.AddressOrName(testutils.TestAddress("recv"))
+normal := users.AddressOrName(testutils.TestAddress("normal"))
+owner := users.AddressOrName(testutils.TestAddress("owner"))
+spender := users.AddressOrName(testutils.TestAddress("spender"))
+recv2 := users.AddressOrName(testutils.TestAddress("recv2"))
+mibu := users.AddressOrName(testutils.TestAddress("mint_burn"))

docs/assets/how-to-guides/creating-grc20/mytoken-1.gno

@@ -0,0 +1,21 @@
+package mytoken
+
+import (
+	"std"
+
+	"gno.land/p/demo/grc/grc20"
+)
+
+var (
+	mytoken *grc20.AdminToken
+	admin   std.Address = "g1us8428u2a5satrlxzagqqa5m6vmuze025anjlj" // set admin account
+)
+
+// init is a constructor function that runs only once (at time of deployment)
+func init() {
+	// provision the token's name, symbol and number of decimals
+	mytoken = grc20.NewAdminToken("Mytoken", "MTKN", 4)
+
+	// set the total supply
+	mytoken.Mint(admin, 1000000*10000) // @administrator (supply = 1 million)
+}

docs/assets/how-to-guides/creating-grc20/mytoken-2.gno

@@ -0,0 +1,83 @@
+func TotalSupply() uint64 {
+	return mytoken.TotalSupply()
+}
+
+func BalanceOf(owner users.AddressOrName) uint64 {
+	balance, err := mytoken.BalanceOf(owner.Resolve())
+	if err != nil {
+		panic(err)
+	}
+	return balance
+}
+
+func Allowance(owner, spender users.AddressOrName) uint64 {
+	allowance, err := mytoken.Allowance(owner.Resolve(), spender.Resolve())
+	if err != nil {
+		panic(err)
+	}
+	return allowance
+}
+
+func Transfer(to users.AddressOrName, amount uint64) {
+	caller := std.PrevRealm().Addr()
+	err := mytoken.Transfer(caller, to.Resolve(), amount)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func Approve(spender users.AddressOrName, amount uint64) {
+	caller := std.PrevRealm().Addr()
+	err := mytoken.Approve(caller, spender.Resolve(), amount)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func TransferFrom(from, to users.AddressOrName, amount uint64) {
+	caller := std.PrevRealm().Addr()
+	err := mytoken.TransferFrom(caller, from.Resolve(), to.Resolve(), amount)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func Mint(address users.AddressOrName, amount uint64) {
+	caller := std.PrevRealm().Addr()
+	assertIsAdmin(caller)
+	err := mytoken.Mint(address.Resolve(), amount)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func Burn(address users.AddressOrName, amount uint64) {
+	caller := std.PrevRealm().Addr()
+	assertIsAdmin(caller)
+	err := mytoken.Burn(address.Resolve(), amount)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func Render(path string) string {
+	parts := strings.Split(path, "/")
+	c := len(parts)
+
+	switch {
+	case path == "":
+		return mytoken.RenderHome()
+	case c == 2 && parts[0] == "balance":
+		owner := users.AddressOrName(parts[1])
+		balance, _ := mytoken.BalanceOf(owner.Resolve())
+		return ufmt.Sprintf("%d\n", balance)
+	default:
+		return "404\n"
+	}
+}
+
+func assertIsAdmin(address std.Address) {
+	if address != admin {
+		panic("restricted access")
+	}
+}

docs/assets/how-to-guides/creating-grc721/mynonfungibletoken-1.gno

@@ -0,0 +1,17 @@
+package mynonfungibletoken
+
+import (
+	"std"
+
+	"gno.land/p/demo/grc/grc721"
+)
+
+var (
+	admin std.Address = "g1us8428u2a5satrlxzagqqa5m6vmuze025anjlj" // set admin account
+	// provision the token's name and symbol
+	mynonfungibletoken = grc721.NewBasicNFT("mynonfungibletoken", "MNFT")
+)
+
+func init() {
+	mintNNFT(admin, 10) // @administrator (supply = 10)
+}

docs/assets/how-to-guides/creating-grc721/mynonfungibletoken-2.gno

@@ -0,0 +1,102 @@
+func mintNNFT(owner std.Address, n uint64) {
+	count := my.TokenCount()
+	for i := count; i < count+n; i++ {
+		tid := grc721.TokenID(ufmt.Sprintf("%d", i))
+		mynonfungibletoken.Mint(owner, tid)
+	}
+}
+
+// Getters
+
+func BalanceOf(user users.AddressOrName) uint64 {
+	balance, err := mynonfungibletoken.BalanceOf(user.Resolve())
+	if err != nil {
+		panic(err)
+	}
+
+	return balance
+}
+
+func OwnerOf(tid grc721.TokenID) std.Address {
+	owner, err := mynonfungibletoken.OwnerOf(tid)
+	if err != nil {
+		panic(err)
+	}
+
+	return owner
+}
+
+func IsApprovedForAll(owner, user users.AddressOrName) bool {
+	return mynonfungibletoken.IsApprovedForAll(owner.Resolve(), user.Resolve())
+}
+
+func GetApproved(tid grc721.TokenID) std.Address {
+	addr, err := mynonfungibletoken.GetApproved(tid)
+	if err != nil {
+		panic(err)
+	}
+
+	return addr
+}
+
+// Setters
+
+func Approve(user users.AddressOrName, tid grc721.TokenID) {
+	err := mynonfungibletoken.Approve(user.Resolve(), tid)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func SetApprovalForAll(user users.AddressOrName, approved bool) {
+	err := mynonfungibletoken.SetApprovalForAll(user.Resolve(), approved)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func TransferFrom(from, to users.AddressOrName, tid grc721.TokenID) {
+	err := mynonfungibletoken.TransferFrom(from.Resolve(), to.Resolve(), tid)
+	if err != nil {
+		panic(err)
+	}
+}
+
+// Admin
+
+func Mint(to users.AddressOrName, tid grc721.TokenID) {
+	caller := std.PrevRealm().Addr()
+	assertIsAdmin(caller)
+	err := mynonfungibletoken.Mint(to.Resolve(), tid)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func Burn(tid grc721.TokenID) {
+	caller := std.PrevRealm().Addr()
+	assertIsAdmin(caller)
+	err := mynonfungibletoken.Burn(tid)
+	if err != nil {
+		panic(err)
+	}
+}
+
+// Render
+
+func Render(path string) string {
+	switch {
+	case path == "":
+		return mynonfungibletoken.RenderHome()
+	default:
+		return "404\n"
+	}
+}
+
+// Util
+
+func assertIsAdmin(address std.Address) {
+	if address != admin {
+		panic("restricted access")
+	}
+}

docs/assets/how-to-guides/porting-solidity-to-gno/porting-1.gno

@@ -0,0 +1,39 @@
+func shouldEqual(t *testing.T, got interface{}, expected interface{}) {
+	t.Helper()
+
+	if got != expected {
+		t.Errorf("expected %v(%T), got %v(%T)", expected, expected, got, got)
+	}
+}
+
+func shouldErr(t *testing.T, err error) {
+	t.Helper()
+	if err == nil {
+		t.Errorf("expected an error, but got nil.")
+	}
+}
+
+func shouldNoErr(t *testing.T, err error) {
+	t.Helper()
+	if err != nil {
+		t.Errorf("expected no error, but got err: %s.", err.Error())
+	}
+}
+
+func shouldPanic(t *testing.T, f func()) {
+	defer func() {
+		if r := recover(); r == nil {
+			t.Errorf("should have panic")
+		}
+	}()
+	f()
+}
+
+func shouldNoPanic(t *testing.T, f func()) {
+	defer func() {
+		if r := recover(); r != nil {
+			t.Errorf("should not have panic")
+		}
+	}()
+	f()
+}

docs/assets/how-to-guides/porting-solidity-to-gno/porting-10.sol

@@ -0,0 +1,29 @@
+/// End the auction and send the highest bid
+/// to the beneficiary.
+function auctionEnd() external {
+    // It is a good guideline to structure functions that interact
+    // with other contracts (i.e. they call functions or send Ether)
+    // into three phases:
+    // 1. checking conditions
+    // 2. performing actions (potentially changing conditions)
+    // 3. interacting with other contracts
+    // If these phases are mixed up, the other contract could call
+    // back into the current contract and modify the state or cause
+    // effects (ether payout) to be performed multiple times.
+    // If functions called internally include interaction with external
+    // contracts, they also have to be considered interaction with
+    // external contracts.
+
+    // 1. Conditions
+    if (block.timestamp < auctionEndTime)
+        revert AuctionNotYetEnded();
+    if (ended)
+        revert AuctionEndAlreadyCalled();
+
+    // 2. Effects
+    ended = true;
+    emit AuctionEnded(highestBidder, highestBid);
+
+    // 3. Interaction
+    beneficiary.transfer(highestBid);
+}

docs/assets/how-to-guides/porting-solidity-to-gno/porting-11.gno

@@ -0,0 +1,17 @@
+func AuctionEnd() {
+	if std.GetHeight() < auctionEndBlock {
+		panic("Auction hasn't ended")
+	}
+
+	if ended {
+		panic("Auction has ended")
+
+	}
+	ended = true
+
+	// Send the highest bid to the recipient
+	banker := std.GetBanker(std.BankerTypeRealmSend)
+	pkgAddr := std.GetOrigPkgAddr()
+
+	banker.SendCoins(pkgAddr, receiver, std.Coins{{"ugnot", int64(highestBid)}})
+}

docs/assets/how-to-guides/porting-solidity-to-gno/porting-12.gno

@@ -0,0 +1,18 @@
+// AuctionEnd() Function Test
+func TestAuctionEnd(t *testing.T) {
+	// Auction is ongoing
+	shouldPanic(t, AuctionEnd)
+
+	// Auction ends
+	highestBid = 3
+	std.TestSkipHeights(500)
+	shouldNoPanic(t, AuctionEnd)
+	shouldEqual(t, ended, true)
+
+	banker := std.GetBanker(std.BankerTypeRealmSend)
+	shouldEqual(t, banker.GetCoins(receiver).String(), "3ugnot")
+
+	// Auction has already ended
+	shouldPanic(t, AuctionEnd)
+	shouldEqual(t, ended, true)
+}