LIGO VS Code Plugin

This plugin is an LSP and Debugger implementations for the LIGO language family.

LSP

Currently, it is highly experimental and may contain bugs. Language Server capabilities on Windows are supported only if running in WSL mode.

Note: You need a LIGO build with support for ligo lsp. LIGO version 0.61.0 and greater will come with support for language server capabilities.

To report bugs in the LIGO Language Server (LLS), please open an issue in GitLab. You should find a file called ligo_language_server.log in your temporary directory. For example, in Linux, this should be inside /tmp/, which might contain information that the devs would find useful to debug your problem.

Version 0.5.0 brings a rewrite of the language server in OCaml to improve the perfomance, stability, and more functionalities implemented in the LIGO compiler.

However, this rewrite doesn't have feature parity yet with the old versions (0.4.29 and older). Those are being actively worked on.

Functionality

Code navigation

• [x] Jump to definition
• [x] Find references (only in open files)
• [x] Folding range
• [ ] Selection range
• [x] Jump to type definition
• [ ] Document symbols
• [x] Document links
• [ ] Workspace symbols

Diagnostics

• [x] Parser diagnostics
• [x] Type-checker diagnostics

Code editing

• [x] Hovers
• [x] Rename symbol (only in open files)
• [ ] Signature help
• [ ] Refactorings

Code completion

• [X] Variable, module and type names
• [X] Record fields
• [X] Module fields
• [X] Keywords and operators
• [ ] Constructors
• [ ] Files
• [ ] Type-aware code completion

Formatting

• [x] Whole document formatting
• [ ] On-type formatting
• [x] Document range formatting (BETA)

It can be configured via extension settings or by creating a .ligopretty file in the project root.

A .ligopretty file should contain a JSON object with

• printWidth : int- max line size (in characters) for file after pretty printing, default is 80.
• tabWidth : int- ident size, default is editor's tab size. Currently supported only for JsLIGO.

All fields are optional. If some option is specified both in a .ligopretty file and in the Ligo Language Server: Max Line Width extension setting, the option from .ligopretty file would be used.

Commands

You can restart the LSP server by executing the LIGO: LIGO Restart LSP Server command. Likewise, commands to start and stop the server are supported as well.

LIGO Options contains various commands for building and running LIGO functions and expressions.

Deploy LIGO contains options to support deploying and generating deploy scripts.

Enabling and disabling features

The extension supports disabling specific LSP features. To do that, add the following in your settings.json:

"ligoLanguageServer.disabledFeatures": [
]

Inside the list, you can write the name of any capability to disable it. For example, to disable formatting:

"ligoLanguageServer.disabledFeatures": [
   "textDocument/formatting"
]

The supported features that may be disabled are listed below:

• textDocument/definition
• textDocument/typeDefinition
• textDocument/references
• textDocument/completion
• textDocument/signatureHelp
• textDocument/foldingRange
• textDocument/selectionRange
• textDocument/documentLink
• textDocument/documentSymbol
• textDocument/hover
• textDocument/rename
• textDocument/prepareRename
• textDocument/formatting
• textDocument/rangeFormatting
• textDocument/codeAction

Note: Please restart the LIGO Language Server after changing this configuration.

Debugger

Connecting the ligo executable

You will need the ligo executable available on your computer. You can find out more from the installation instructions.

You can specify a path to the ligo executable in settings.json. The debugger will look for it in the following order:

1. The debugger will use this path if this field is filled.
2. If this field is blank, the debugger will try to find the ligo executable in the $PATH variable.
3. Otherwise, the debugger will use the path from the $LIGO_BINARY_PATH variable.

Also, if you prefer using ligo from the Docker image then you can specify a path to the next script which runs ligo from Docker:

#!/bin/sh
docker run --rm -v $(pwd):$(pwd) -w $(pwd) ligolang/ligo:{ligo-version} "$@"

where {ligo-version} is your preferred ligo version (e.g. 0.70.1).

At this moment running ligo from Docker is slow, so it's better to use the static binary.

Functionality support

What is supported as part of MVP:

• Contracts using the common functionality;
• Convenient supply of endpoint / parameter / storage with last value remembering and two input modes;
• All stepping commands (including Step Back) with statement and expression granularities;
• Display of variables, including records, constructors, lists, and combinations of them;
• Stack frames display;
• Breakpoints (but not guaranteed to work properly in all the cases at the moment);
• Providing custom environment (Tezos.get_now, Tezos.get_balance, etc).

Bits of functionality that will be added very soon:

• Contracts related functionality:
  • [ ] Running contract with embedded Michelson.
  • [ ] Running contract with other contracts origination.
  • [ ] Running contracts with global constants.
  • [ ] Running corner cases of contracts with tickets (the current support is partial).
• Others:
  • [ ] Work with the downloaded packages.
  • [ ] Speed up debug session start (currently it takes long for relatively large contracts).

Next we will work on extending the core functionality step by step: add full breakpoints support, viewing inner parts of variables' values, simpler ways of starting a debug session, logpoints support, and many other improvements.

Also some notes:

• Due to some limitations on ligo executable's side and on our side, an invalid Michelson code may be produced. If you encounter this problem, please contact us.
• We slightly change the Michelson code, this may result in minor differences (e.g. PACKed code may result in a different bytestring).

Running the debugger

You can press F5 to start debugging a LIGO contract. Upon the launch of the debugger, you will be asked for a value for the parameter, and a value for the storage. You can provide a LIGO module entrypoint in your launch.json with (*@AskOnStart@*). It will ask you to choose an entrypoint for your contract. If you want to hardcode it, then you can write it in this field.

"moduleName": "(*@AskOnStart@*)" <-- will ask you to choose an entrypoint via quickpick

"moduleName": "Main1" <-- will use "Main1" as module entrypoint

Use F11 (or press "Step Into") to step through LIGO code in details.

Launch configuration

Passing parameter and storage

The parameter and storage fields define what will be passed as run arguments.

It is possible to hardcode a concrete value both in LIGO and Michelson. You just need to specify its origin in parameterLang or storageLang fields. Note, that these fields are optional and the default value for them is LIGO. For example:

...
"parameter": "5n",
"parameterLang": "LIGO", <-- this field is optional
"storage": "Left 42",
"storageLang": "Michelson",
...

However, usually you might prefer using the auto-filled values like (*@AskOnStart@*) that would request the actual value upon starting a debug session.

In both cases you can use complex expressions, e.g. { a = 1; b = 2 } for record definition or even let x = 9 in x * x + 5 in Cameligo. The dialect of the passed expressions must match the dialect of the contract.

It is possible to refer to constants declared in the contract and even call functions.

In case you need to supply a value in the lower-level Michelson format, just use switch button in the top right corner of input box.

Specifying a LIGO entrypoint

Entrypoints in LIGO are marked with @entry annotation. For example:

[@entry]
let increment (a : int) (st : storage) : ret = ...

[@entry]
let decrement (a : int) (st : storage) : ret = ...

If you want to debug a specific entrypoint then you can use entrypoint field in launch.json. Example:

{
  "entrypoint": "increment",
  "parameter": 42
}

You can omit it or use (*@AskOnStart@*). In both cases, it will ask you for an entrypoint if your contract has more than one.

Passing a custom environment

The debugger supports providing a custom environment for your contracts. You can customize it in the contractEnv field. An example of configuration:

...
"contractEnv": {
  "now": "2020-01-01T00:00:00Z",
  "level": "10000",
  "sender": "tz1hTK4RYECTKcjp2dddQuRGUX5Lhse3kPNY",
  "source": "tz1hTK4RYECTKcjp2dddQuRGUX5Lhse3kPNY",
  "self": "KT1XQcegsEtio9oGbLUHA8SKX4iZ2rpEXY9b",
  "amount": "0",
  "balance": "1000000",
  "chainId": "NetXH12Aer3be93",
  "votingPowers": {
    "kind": "simple",
    "contents": {
      "tz1aZcxeRT4DDZZkYcU3vuBaaBRtnxyTmQRr": "100"
    }
  }
}
...

All these fields are optional. Let's describe what they mean:

1. now. The value returned by Tezos.get_now(). Default: current system time.
2. level. The value returned by Tezos.get_level(). Default: "10000".
3. sender. The value returned by Tezos.get_sender(). Default: "tz1hTK4RYECTKcjp2dddQuRGUX5Lhse3kPNY".
4. source. The value returned by Tezos.get_source(). Default: "tz1hTK4RYECTKcjp2dddQuRGUX5Lhse3kPNY".
5. self. The value returned by Tezos.get_self_address(). Default: "KT1XQcegsEtio9oGbLUHA8SKX4iZ2rpEXY9b".
6. amount. The value returned by Tezos.get_amount(). Default: "0".
7. balance. The value returned by Tezos.get_balance(). Default: "1000000".
8. chainId. The value returned by Tezos.get_chain_id(). Default: "NetXH12Aer3be93".
9. votingPowers. At this moment only the simple kind is supported. In the contents field you should specify key hashes and their voting powers. Default: { "kind": "simple", "contents": { "tz1aZcxeRT4DDZZkYcU3vuBaaBRtnxyTmQRr": "100" } }.

Providing configuration in LIGO

You can also provide a configuration using one of the LIGO dialects. It could be done by using Debug: Create configuration in LIGO for the debugger command (Ctrl + Shift + P shortcut for opening the command palette). It will ask you for a directory where the config would be created and for a config name. Note, that it will overwrite the file with the same name.

An example of the config (in CameLIGO):

let contract_env =
  { now           = "2020-01-01T00:00:00Z"
  ; balance       = 1tez
  ; amount        = 2tez
  ; self          = "KT1XQcegsEtio9oGbLUHA8SKX4iZ2rpEXY9b"
  ; source        = "tz1hTK4RYECTKcjp2dddQuRGUX5Lhse3kPNY"
  ; sender        = "tz1hTK4RYECTKcjp2dddQuRGUX5Lhse3kPNY"
  ; chain_id      = "NetXH12Aer3be93"
  ; level         = 10000
  ; voting_powers = Map.literal
      [ "tz1aZcxeRT4DDZZkYcU3vuBaaBRtnxyTmQRr", 40
      ; "tz1hTK4RYECTKcjp2dddQuRGUX5Lhse3kPNY", 60
      ]
  }

let config =
  { parameter    = "*parameter value*"
  ; storage      = "*storage value*"
  ; program      = "*path to program*"
  ; module_name  = "*module name*"
  ; entrypoint   = "*entrypoint name*"
  ; log_dir      = "*log directory*"
  ; contract_env = contract_env
  }

Note, that all these fields are optional and you can omit them. The debugger will ask for them if they're needed (e.g. an entrypoint or parameter). The only required object here is config.

Don't forget to add a path to the LIGO config into your launch.json configuration (configPath field). The debugger doesn't do this automatically. You can set (*@AskOnStart@*) command there and the debugger will ask you for a config path.

Also, the LIGO configuration will overlap the existing launch.json one. For example, if you haven't specified the now field in the contract_env but you have it in the launch.json, then it will be set to default value.

Stepping

Use the available Next, StepIn, and other commands to go over the contract execution. Stepping back is supported too.

You can change the stepping granularity with a button at the lower panel:

which is useful for evaluating complex expressions step-by-step.

Use Ctrl + F10 (Cmd + F10 on Mac) to switch between the last and currently selected granularities.

FAQ

I've set "moduleName": "(*@AskOnStart@*)" in the configuration, and I'm still not asked for a module name when starting a debug session.

We automatically detect the list of module names in the file, and in case it contains only one, we skip the selection stage. Make sure that your module name is a valid one.

I've set "entrypoint": "(*@AskOnStart@*)" in the configuration, and I'm still not asked for an entrypoint when starting a debug session.

We automatically detect the list of entrypoints in the contract, and in case it contains only one entrypoint, we skip the selection stage.

Debugger stepping order is weird

Before being executed, LIGO contracts are converted to Michelson language (which all Tezos smart contracts are eventually written in), and generally some things get reordered to get a more optimal contract.

For example, when executing binary operations, the right operand is computed first.

In debugger we try to preserve the execution order, otherwise runs in production and in debugger could have different outcomes. As example of this change in result imagine a binary operation, both sides of which result in a failure.

However, some reorderings can be safely illiminated. We try to handle such cases accordingly, but if you think this is your case, we would appreciate if you reported this issue.

I see many instances of the same function/value in the variables pane

It's okay. At this moment debugger doesn't support polymorphic types in the variables pane, so, you'll see all monomorphed variants that are used in your contract.

Debugger says that my contract has an infinite loop but it doesn't

By default the debugger will do 1000 steps and after that will assume that a contract has an infinite loop. You can change the max steps value in the settings. By step we mean step in expression (pre + post) granularity.

From some moment I see %field% {AskOnStart} does not exist error

We changed command braces from { and } to (*@ and @*) because the previous ones were conflicting with LIGO record notation. So, now you need to write (*@AskOnStart@*) instead of {AskOnStart}.