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Valast converts Go values at runtime into theirgo/ast equivalent, e.g.:

x:=&foo.Bar{a:"hello world!",B:1.234,}fmt.Println(valast.String(x))

Prints string:

&foo.Bar{a:"hello world!",B:1.234}

This can be useful for debugging and testing, you may think of it as a more comprehensive and configurable version of thefmt package's%+v and%#v formatting directives. It is similar to e.g.repr in Python.

• Produces Go code via ago/ast, defers formatting to the best-in-class Go formattergofumpt.
• Fully handles unexported fields, types, and values (optional.)
• Strong emphasis on being used for producing valid Go code that can be copy & pasted directly into e.g. tests.
• Extensively tested, over 88 tests and handling numerous edge cases (such as pointers to unaddressable literal values like&"foo" properly, and evenfinding bugs in alternative packages').
• Provide custom AST representations for your types withvalast.RegisterType(...).

The following are alternatives to Valast, making note of the differences we found that let us to create Valast:

• github.com/davecgh/go-spew
  • may be inactive
  • Produces Go-like output, but not Go syntax.
• github.com/shurcooL/go-goon (based on go-spew)
  • Produces valid Go syntax, but not via ago/ast.
  • Produces less idiomatic/terse results)
  • Was deprecated in favor of valast.
• github.com/alecthomas/repr
  • Produces Go syntax, but not always valid code (e.g. can emit illegal&23, whereas Valast will emit a valid expressionvalast.Addr(23).(int)), not via ago/ast.
  • Does not handle unexported fields/types/values.

You may also wish to look atautogold andgo-cmp, which aim to solve the "compare Go values in a test" problem.