blob: ef787b750e5a7f2aa4250f5b046596432f25056c [file] [log] [blame] [edit]
package source
import (
"go/ast"
"golang.org/x/tools/internal/lsp/protocol"
errors "golang.org/x/xerrors"
)
const (
BREAK = "break"
CASE = "case"
CHAN = "chan"
CONST = "const"
CONTINUE = "continue"
DEFAULT = "default"
DEFER = "defer"
ELSE = "else"
FALLTHROUGH = "fallthrough"
FOR = "for"
FUNC = "func"
GO = "go"
GOTO = "goto"
IF = "if"
IMPORT = "import"
INTERFACE = "interface"
MAP = "map"
PACKAGE = "package"
RANGE = "range"
RETURN = "return"
SELECT = "select"
STRUCT = "struct"
SWITCH = "switch"
TYPE = "type"
VAR = "var"
)
// keyword looks at the current scope of an *ast.Ident and recommends keywords
func (c *completer) keyword() error {
if _, ok := c.path[0].(*ast.Ident); !ok {
// TODO(golang/go#34009): Support keyword completion in any context
return errors.Errorf("keywords are currently only recommended for identifiers")
}
// Track which keywords we've already determined are in a valid scope
// Use score to order keywords by how close we are to where they are useful
valid := make(map[string]float64)
// only suggest keywords at the begnning of a statement
switch c.path[1].(type) {
case *ast.BlockStmt, *ast.CommClause, *ast.CaseClause, *ast.ExprStmt:
default:
return nil
}
// Filter out keywords depending on scope
// Skip the first one because we want to look at the enclosing scopes
for _, n := range c.path[1:] {
switch node := n.(type) {
case *ast.CaseClause:
// only recommend "fallthrough" and "break" within the bodies of a case clause
if c.pos > node.Colon {
valid[BREAK] = stdScore
// TODO: "fallthrough" is only valid in switch statements
valid[FALLTHROUGH] = stdScore
}
case *ast.CommClause:
if c.pos > node.Colon {
valid[BREAK] = stdScore
}
case *ast.TypeSwitchStmt, *ast.SelectStmt, *ast.SwitchStmt:
valid[CASE] = stdScore + lowScore
valid[DEFAULT] = stdScore + lowScore
case *ast.ForStmt:
valid[BREAK] = stdScore
valid[CONTINUE] = stdScore
// This is a bit weak, functions allow for many keywords
case *ast.FuncDecl:
if node.Body != nil && c.pos > node.Body.Lbrace {
valid[DEFER] = stdScore - lowScore
valid[RETURN] = stdScore - lowScore
valid[FOR] = stdScore - lowScore
valid[GO] = stdScore - lowScore
valid[SWITCH] = stdScore - lowScore
valid[SELECT] = stdScore - lowScore
valid[IF] = stdScore - lowScore
valid[ELSE] = stdScore - lowScore
valid[VAR] = stdScore - lowScore
valid[CONST] = stdScore - lowScore
}
}
}
for ident, score := range valid {
if c.matcher.Score(ident) > 0 {
c.items = append(c.items, CompletionItem{
Label: ident,
Kind: protocol.KeywordCompletion,
InsertText: ident,
Score: score,
})
}
}
return nil
}