HOL4 mode for Visual Studio Code

Support for working with the HOL4 interactive theorem prover in Visual Studio Code. This plugin provides the required functionality to maintain a HOL session in an editor window, basic syntax highlighting, and basic unicode input completion. The plugin can index source files in the users current directory and provides basic go-to-definition functionality for theorems, function definitions, and inductive relations.

Requirements

Expects a HOL4 installation to exist, and the environment variable $HOLDIR to point to this installation. The HOL4 homepage can be found here and its GitHub repository here.

Extension Settings

It is possible to toggle the indexing of theorems and definitions in the workspace from the settings by the key: hol4-mode.indexing to false.

Suggested additions to settings.json for use with VSCodeVim, somewhat corresponding to the HOL4 Vim mode defaults:

{
    "vim.visualModeKeyBindings": [
        {
            "before": [ "<leader>", "e" ],
            "commands": [ "hol4-mode.sendTactic" ]
        },
        {
            "before": [ "<leader>", "s" ],
            "commands": [ "hol4-mode.sendSelection" ]
        },
    ],
    "vim.normalModeKeyBindings": [
        {
            "before": [ "<leader>", "h" ],
            "commands": [ "hol4-mode.startSession" ]
        },
        {
            "before": [ "<leader>", "<leader>", "x" ],
            "commands": [ "hol4-mode.stopSession" ]
        },
        {
            "before": [ "<leader>", "s" ],
            "commands": [ "hol4-mode.sendSelection" ]
        },
        {
            "before": [ "<leader>", "<leader>", "s" ],
            "commands": [ "hol4-mode.sendUntilCursor" ]
        },
        {
            "before": [ "<leader>", "g" ],
            "commands": [ "hol4-mode.sendGoal" ]
        },
        {
            "before": [ "<leader>", "S" ],
            "commands": [ "hol4-mode.sendSubgoal" ]
        },
        {
            "before": [ "<leader>", "e" ],
            "commands": [ "hol4-mode.sendTactic" ]
        },
        {
            "before": [ "<leader>", "p" ],
            "commands": [ "hol4-mode.proofmanShow" ]
        },
        {
            "before": [ "<leader>", "b" ],
            "commands": [ "hol4-mode.proofmanBack" ]
        },
        {
            "before": [ "<leader>", "R" ],
            "commands": [ "hol4-mode.proofmanRestart" ]
        },
        {
            "before": [ "<leader>", "r" ],
            "commands": [ "hol4-mode.proofmanRotate" ]
        },
        {
            "before": [ "<leader>", "d" ],
            "commands": [ "hol4-mode.proofmanDrop" ]
        },
        {
            "before": [ "<leader>", "y" ],
            "commands": [ "hol4-mode.toggleShowTypes" ]
        },
        {
            "before": [ "<leader>", "a" ],
            "commands": [ "hol4-mode.toggleShowAssums" ]
        },
        {
            "before": [ "<leader>", "c" ],
            "commands": [ "hol4-mode.interrupt" ]
        }
    ]
}

Known Issues

• Syntax highlighting is lacking. Logical terms are especially bad. The situation could be improved by implementing a HOL language server.
• There is some hacky code that attempts to strip ML comments from input that is being sent to HOL. Currently, this does not properly deal with nested comments, or comment tokens that exist within string literals.
• Comments are not stripped from tactic text.
• load calls are not inserted when calls to qualified ML code is made.
• Location pragmas are not inserted at calls to {Co}Inductive, Datatype, Theorem, nor in term quotations.
• Definitions created with Define are not properly indexed.
• Automatically generated theorems (for example, inductions) are not properly indexed.
• The hover/symbol-providers won't work on fully qualified identifiers (such as myTheory.my_theorem).