compiler_cache v1.1.0 CompilerCache behaviour

A callback-based compilation cache GenServer.

This genserver caches compiled expressions into a module.

While expressions are compiling (which can take some time), it returns values by calling Code.eval_quoted/3 which is more efficient in the short run.

Internally this uses a fixed pool of atoms as not to exhaust the atom table. A LRU cache mechanism is used to clean up unused expressions.

Example usage

defmodule MyExpressionParser do
  use CompilerCache

  def create_ast(expression) do
    # Create your AST here based on the expression, e.g.:
    {:ok, ast} = Code.string_to_quoted(expr)
    {ast, []}
  end
end

Configuration

In the use statement it is possible to give extra compile-time options to the compiler cache, like this:

use CompilerCache, [max_size: 1000, cache_misses: 0]

The possible options are:

  • input_name - The name of the variable that’s being used for the input to the compiled function. Defaults to input.

  • max_size - how many entries we can have in the cache table; defaults to 10_000.

  • cache_misses - after how many cache misses the compiler should start compiling the module. Defaults to 1, which means that the first expression will not start compilation, but the second hit will. When specifying :none, no caching will be done. (for test purposes)

  • max_ttl - how long entries are allowed to linger in the cache (without being called), in seconds. Defaults to 10.

Summary

Callbacks

Create the Abstract Syntax Tree and the execution context for the given expression

Start the given compiler cache

Callbacks

create_ast(expression)
create_ast(expression :: any) :: {ast :: term, opts :: [term]}

Create the Abstract Syntax Tree and the execution context for the given expression.

start_link()
start_link() :: GenServer.on_start

Start the given compiler cache