Visualize the AST structure from ASTNode object, source file, or source code string.
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README.md

AST Viewer for Crysal

Visualize the AST structure from ASTNode object, source file, or source code string.

The target compiler version is 0.27.0.

Installation

Add this to your application's shard.yml:

dependencies:
  ast_viewer:
    github: arcage/ast_viewer.cr

Usage

require "ast_viewer"

# From ASTNode object
viewer = ASTViewer.from_node(node_object)

# From source file
viewer = ASTViewer.from_file("source_file.cr")

# From source code string
source_code = <<-SRC
def foo(bar : Int32) : String
  bar.to_s
end

buz = foo(0)
SRC
viewer = ASTViewer.from_source(source_code)

puts viewer

Result exapmle:

Output

If you doesn't want to colorize the output, set colorize property to false:

viewer.colorize = false

When the AST is parsed from the source code that has syntax error, the error message simillar to the compile time error will be displaied.

Result example 2(a = [1, 2, 3 is given):

Syntax error in :1: expecting token ']', not 'EOF'

a = [1, 2, 3
            ^

Notice

This shard will parse source code on the syntax level only, not the semantic level.

  • Any AST transformations are not applied. (require file, unless to if conversion ...)
  • Semantic errors are not checked. (method existence, type mismatch ...)

Contributors

  • arcage ʕ·ᴥ·ʔAKJ - creator, maintainer