anselme/doc/api.md

This document describes how to use the main Anselme modules. This is generated automatically from the source files.

Note that this file only describes the anselme and state.State modules, which are only a selection of what I consider to be the "public API" of Anselme that I will try to keep stable. If you need more advanced control on Anselme, feel free to look into the other source files to find more; the most useful functions should all be reasonably commented.

anselme

The main module.

Usage:

local anselme = require("anselme")

-- create a new state
local state = anselme.new()
state:load_stdlib()

-- read an anselme script file
local f = assert(io.open("script.ans"))
local script = anselme.parse(f:read("*a"), "script.ans")
f:close()

-- load the script in a new branch
local run_state = state:branch()
run_state:run(script)

-- run the script
while run_state:active() do
	local e, data = run_state:step()
	if e == "text" then
		for _, l in ipairs(data) do
			print(l:format(run_state))
		end
	elseif e == "choice" then
		for i, l in ipairs(data) do
			print(("%s> %s"):format(i, l:format(run_state)))
		end
		local choice = tonumber(io.read("*l"))
		data:choose(choice)
	elseif e == "return" then
		run_state:merge()
	elseif e == "error" then
		error(data)
	end
end

.version

Global version string. Follow semver.

defined at line 57 of anselme.lua: version = "2.0.0-alpha",

.versions

Table containing per-category version numbers. Incremented by one for any change that may break compatibility.

defined at line 60 of anselme.lua: versions = {

.language

Version number for languages and standard library changes.

defined at line 62 of anselme.lua: language = 27,

.save

Version number for save/AST format changes.

defined at line 64 of anselme.lua: save = 4,

.api

Version number for Lua API changes.

defined at line 66 of anselme.lua: api = 8

.parse (code, source)

Parse a code string and return the generated AST.

source is an optional string; it will be used as the code source name in error messages.

Usage:

local ast = anselme.parse("1 + 2", "test")
ast:eval()

defined at line 78 of anselme.lua: parse = function(code, source)

.new ()

Return a new State.

defined at line 82 of anselme.lua: new = function()

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State

Contains all state relative to an Anselme interpreter. Each State is fully independant from each other. Each State can run a single script at a time, and variable changes are isolated between each State (see branching).

:load_stdlib ()

Load standard library. You will probably want to call this on every State right after creation.

defined at line 41 of state/State.lua: load_stdlib = function(self)

Branching and merging

.branch_id

Name of the branch associated to this State.

defined at line 48 of state/State.lua: branch_id = "main",

.source_branch_id

Name of the branch this State was branched from.

defined at line 50 of state/State.lua: source_branch_id = "main",

:branch ()

Return a new branch of this State.

Branches act as indepent copies of this State where any change will not be reflected in the source State until it is merged back into the source branch. Note: probably makes the most sense to create branches from the main State only.

defined at line 56 of state/State.lua: branch = function(self)

:merge ()

Merge everything that was changed in this branch back into the main State branch.

Recommendation: only merge if you know that the state of the variables is consistent, for example at the end of the script, checkpoints, ... If your script errored or was interrupted at an unknown point in the script, you might be in the middle of a calculation and variables won't contain values you want to merge.

defined at line 65 of state/State.lua: merge = function(self)

Variable definition

:define (name, value, func, raw_mode)

Define a value in the global scope, converting it from Lua to Anselme if needed.

• for lua functions: define("name", "(x, y, z=5)", function(x, y, z) ... end), where arguments and return values of the function are automatically converted between anselme and lua values
• for other lua values: define("name", value)
• for anselme AST: define("name", value)

name can be prefixed with symbol modifiers, for example ":name" for a constant variable.

If raw_mode is true, no anselme-to/from-lua conversion will be performed in the function. The function will receive the state followed by AST nodes as arguments, and is expected to return an AST node.

defined at line 83 of state/State.lua: define = function(self, name, value, func, raw_mode)

:define_local (name, value, func, raw_mode)

Same as :define, but define the expression in the current scope.

defined at line 89 of state/State.lua: define_local = function(self, name, value, func, raw_mode)

For anything more advanced, you can directly access the current scope stack stored in state.scope. See state/ScopeStack.lua for details; the documentation is not as polished as this file but you should still be able to find your way around.

Saving and loading persistent variables

:save ()

Return a serialized (string) representation of all persistent variables in this State.

This can be loaded back later using :load.

defined at line 101 of state/State.lua: save = function(self)

:load (save)

Load a string generated by :save.

Variables that already exist will be overwritten with the loaded data.

defined at line 108 of state/State.lua: load = function(self, save)

Current script state

:active ()

Indicate if a script is currently loaded in this branch.

defined at line 122 of state/State.lua: active = function(self)

:state ()

Returns "running" if a script is currently loaded and running (i.e. this was called from the script).

Returns "active" if a script is loaded but not currently running (i.e. the script has not started or is waiting on an event).

Returns "inactive" if no script is loaded.

defined at line 130 of state/State.lua: state = function(self)

:run (code, source)

Load a script in this branch. It will become the active script.

code is the code string or AST to run, source is the source name string to show in errors (optional).

Note that this will only load the script; execution will only start by using the :step method. Will error if a script is already active in this State.

defined at line 142 of state/State.lua: run = function(self, code, source)

:step ()

When a script is active, will resume running it until the next event.

Will error if no script is active.

Returns event type string, event data.

defined at line 155 of state/State.lua: step = function(self)

:interrupt (code, source)

Stops the currently active script.

Will error if no script is active.

If code is given, the script will not be disabled but instead will be immediately replaced with this new script. The new script will then be started on the next :step and will preserve the current scope. This can be used to trigger an exit function or similar in the active script.

defined at line 173 of state/State.lua: interrupt = function(self, code, source)

:eval (code, source)

Evaluate an expression in the global scope.

This can be called from outside a running script, but an error will be triggered the expression raise any event other than return.

• returns AST in case of success. Run :to_lua(state) on it to convert to a Lua value.
• returns nil, error message in case of error.

defined at line 194 of state/State.lua: eval = function(self, code, source)

:eval_local (code, source)

Same as :eval, but evaluate the expression in the current scope.

defined at line 201 of state/State.lua: eval_local = function(self, code, source)

If you want to perform more advanced manipulation of the resulting AST nodes, look at the ast modules. In particular, every Node inherits the methods from ast.abstract.Node. Otherwise, each Node has its own module file defined in the ast/ directory.

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