Method extract_go_expr

cursorcontext.go:196–250

Starting from the token under the cursor move back and extract something that resembles a valid Go primary expression. Examples of primary expressions from Go spec: x 2 (s + ".txt") f(3.1415, true) Point{1, 2} m["foo"] s[i : j + 1] obj.color f.p[i].x() As you can see we can move through all of them

()

// Of course there are also slightly more complicated rules for brackets:
//   ident{}.ident()[5][4](), etc.
func (this *token_iterator) extract_go_expr() string {
	orig := this.token_index

	// Contains the type of the previously scanned token (initialized with
	// the token right under the cursor). This is the token to the *right* of
	// the current one.
	prev := this.token().tok
loop:
	for {
		if !this.go_back() {
			return token_items_to_string(this.tokens[:orig])
		}
		switch this.token().tok {
		case token.PERIOD:
			// If the '.' is not followed by IDENT, it's invalid.
			if prev != token.IDENT {
				break loop
			}
		case token.IDENT:
			// Valid tokens after IDENT are '.', '[', '{' and '('.
			switch prev {
			case token.PERIOD, token.LBRACK, token.LBRACE, token.LPAREN:
				// all ok
			default:
				break loop
			}
		case token.RBRACE:
			// This one can only be a part of type initialization, like:
			//   Dummy{}.Hello()
			// It is valid Go if Hello method is defined on a non-pointer receiver.
			if prev != token.PERIOD {
				break loop
			}
			this.skip_to_balanced_pair()
		case token.RPAREN, token.RBRACK:
			// After ']' and ')' their opening counterparts are valid '[', '(',
			// as well as the dot.
			switch prev {
			case token.PERIOD, token.LBRACK, token.LPAREN:
				// all ok
			default:
				break loop
			}
			this.skip_to_balanced_pair()
		default:
			break loop
		}
		prev = this.token().tok
	}
	expr := token_items_to_string(this.tokens[this.token_index+1 : orig])
	if *g_debug {
		log.Printf("extracted expression tokens: %s", expr)
	}
	return expr
}

// Given a slice of token_item, reassembles them into the original literal
// expression.