This package is nowhere near finished - in fact not even started. Please don't try to use it yet!

I'm struggling to find a real-world use for this package, so I'm pausing development.

Decorated Syntax Selectors

This package attempts to implement a dialect of CSS Selectors that can be used to easily select nodes in a Go syntax tree. Specifically, the Decorated Syntax Tree defined by github.com/dave/dst.

Names

Name	Example
Node	Ident in Ident
Interface	Expr
Field	Body in FuncLit
Definition	foo in Field.Names*, ImportSpec.Name, ValueSpec.Names**, TypeSpec.Name, FuncDecl.Name, File.Name, AssignStmt.Lhs***
Reference	foo in Ident.Name
Package	foo.bar/baz in Ident.Path

* Field.Names - all names are applied to the Field
** ValueSpec.Names - all names are applied to the ValueSpec node, and each name is applied to it's corresponding Expr node in Values
*** AssignStmt.Lhs - only when AssignStmt.Tok == token.DEFINE, all names are applied to the AssignStmt node, and each name is applied to it's corresponding Expr node in Rhs

Proposed DSS Selectors for DST

Implemented	Selector	Example	Example description
☐	.field	.Fun	Selects all child nodes in the field Fun
☐	#name	#main	Selects all nodes that define the name main
☐	node	CallExpr	Selects all CallExpr nodes
☐	interface	Expr	Selects all nodes that satisfy the Expr interface
☐	node,node	CallExpr, Ident	Selects all CallExpr nodes and all Ident nodes
☐	node node	CallExpr Ident	Selects all Ident nodes inside CallExpr nodes
☐	node>node	CallExpr > Ident	Selects all Ident nodes where the parent is a CallExpr node

Examples

func main() {
	foo, bar := 1 + 1, 2 + 2
}

type T struct {
	i, j int
}

FuncDecl#main Expr#foo BinaryExpr -> 1 + 1

#T #i.Type -> int

CSS Selectors for HTML

Proposed	Implemented	Selector	Example	Example description
☒	☐	.class	.intro	Selects all elements with class="intro"
☒	☐	#id	#firstname	Selects the element with id="firstname"
☐	☐	*	*	Selects all elements
☒	☐	element	p	Selects all <p> elements
☒	☐	element,element	div, p	Selects all <div> elements and all <p> elements
☒	☐	element element	div p	Selects all <p> elements inside <div> elements
☒	☐	element>element	div > p	Selects all <p> elements where the parent is a <div> element
☐	☐	element+element	div + p	Selects all <p> elements that are placed immediately after <div> elements
☐	☐	element1~element2	p ~ ul	Selects every <ul> element that are preceded by a <p> element
☐	☐	[attribute]	[target]	Selects all elements with a target attribute
☐	☐	[attribute=value]	[target=_blank]	Selects all elements with target="_blank"
☐	☐	[attribute~=value]	[title~=flower]	Selects all elements with a title attribute containing the word "flower"
☐	☐	`[attribute	=value]`	`[lang
☐	☐	[attribute^=value]	a[href^="https"]	Selects every <a> element whose href attribute value begins with "https"
☐	☐	[attribute$=value]	a[href$=".pdf"]	Selects every <a> element whose href attribute value ends with ".pdf"
☐	☐	[attribute*=value]	a[href*="w3schools"]	Selects every <a> element whose href attribute value contains the substring "w3schools"
☐	☐	:active	a:active	Selects the active link
☐	☐	::after	p::after	Insert something after the content of each <p> element
☐	☐	::before	p::before	Insert something before the content of each <p> element
☐	☐	:checked	input:checked	Selects every checked <input> element
☐	☐	:default	input:default	Selects the default <input> element
☐	☐	:disabled	input:disabled	Selects every disabled <input> element
☐	☐	:empty	p:empty	Selects every <p> element that has no children (including text nodes)
☐	☐	:enabled	input:enabled	Selects every enabled <input> element
☐	☐	:first-child	p:first-child	Selects every <p> element that is the first child of its parent
☐	☐	::first-letter	p::first-letter	Selects the first letter of every <p> element
☐	☐	::first-line	p::first-line	Selects the first line of every <p> element
☐	☐	:first-of-type	p:first-of-type	Selects every <p> element that is the first <p> element of its parent
☐	☐	:focus	input:focus	Selects the input element which has focus
☐	☐	:hover	a:hover	Selects links on mouse over
☐	☐	:in-range	input:in-range	Selects input elements with a value within a specified range
☐	☐	:indeterminate	input:indeterminate	Selects input elements that are in an indeterminate state
☐	☐	:invalid	input:invalid	Selects all input elements with an invalid value
☐	☐	:lang(language)	p:lang(it)	Selects every <p> element with a lang attribute equal to "it" (Italian)
☐	☐	:last-child	p:last-child	Selects every <p> element that is the last child of its parent
☐	☐	:last-of-type	p:last-of-type	Selects every <p> element that is the last <p> element of its parent
☐	☐	:link	a:link	Selects all unvisited links
☐	☐	:not(selector)	:not(p)	Selects every element that is not a <p> element
☐	☐	:nth-child(n)	p:nth-child(2)	Selects every <p> element that is the second child of its parent
☐	☐	:nth-last-child(n)	p:nth-last-child(2)	Selects every <p> element that is the second child of its parent, counting from the last child
☐	☐	:nth-last-of-type(n)	p:nth-last-of-type(2)	Selects every <p> element that is the second <p> element of its parent, counting from the last child
☐	☐	:nth-of-type(n)	p:nth-of-type(2)	Selects every <p> element that is the second <p> element of its parent
☐	☐	:only-of-type	p:only-of-type	Selects every <p> element that is the only <p> element of its parent
☐	☐	:only-child	p:only-child	Selects every <p> element that is the only child of its parent
☐	☐	:optional	input:optional	Selects input elements with no "required" attribute
☐	☐	:out-of-range	input:out-of-range	Selects input elements with a value outside a specified range
☐	☐	::placeholder	input::placeholder	Selects input elements with placeholder text
☐	☐	:read-only	input:read-only	Selects input elements with the "readonly" attribute specified
☐	☐	:read-write	input:read-write	Selects input elements with the "readonly" attribute NOT specified
☐	☐	:required	input:required	Selects input elements with the "required" attribute specified
☐	☐	:root	:root	Selects the document's root element
☐	☐	::selection	::selection	Selects the portion of an element that is selected by a user
☐	☐	:target	#news:target	Selects the current active #news element (clicked on a URL containing that anchor name)
☐	☐	:valid	input:valid	Selects all input elements with a valid value
☐	☐	:visited	a:visited	Selects all visited links