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moby--moby/builder/parser/line_parsers.go
Erik Hollensbe d6c0bbc3cb builder: add command handling to evaluator.
Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
2014-08-27 18:52:30 -07:00

108 lines
2.5 KiB
Go

package parser
import (
"encoding/json"
"strconv"
"strings"
)
// ignore the current argument. This will still leave a command parsed, but
// will not incorporate the arguments into the ast.
func parseIgnore(rest string) (*Node, error) {
return blankNode(), nil
}
func parseSubCommand(rest string) (*Node, error) {
_, child, err := parseLine(rest)
if err != nil {
return nil, err
}
return &Node{Children: []*Node{child}}, nil
}
// parse environment like statements. Note that this does *not* handle
// variable interpolation, which will be handled in the evaluator.
func parseEnv(rest string) (*Node, error) {
node := blankNode()
rootnode := node
strs := TOKEN_WHITESPACE.Split(rest, 2)
node.Value = strs[0]
node.Next = blankNode()
node.Next.Value = strs[1]
return rootnode, nil
}
// parses a whitespace-delimited set of arguments. The result is effectively a
// linked list of string arguments.
func parseStringsWhitespaceDelimited(rest string) (*Node, error) {
node := blankNode()
rootnode := node
prevnode := node
for _, str := range TOKEN_WHITESPACE.Split(rest, -1) { // use regexp
prevnode = node
node.Value = str
node.Next = blankNode()
node = node.Next
}
// XXX to get around regexp.Split *always* providing an empty string at the
// end due to how our loop is constructed, nil out the last node in the
// chain.
prevnode.Next = nil
return rootnode, nil
}
// parsestring just wraps the string in quotes and returns a working node.
func parseString(rest string) (*Node, error) {
return &Node{rest, nil, nil}, nil
}
// parseJSON converts JSON arrays to an AST.
func parseJSON(rest string) (*Node, error) {
var (
myJson []interface{}
next = blankNode()
orignext = next
prevnode = next
)
if err := json.Unmarshal([]byte(rest), &myJson); err != nil {
return nil, err
}
for _, str := range myJson {
switch str.(type) {
case float64:
str = strconv.FormatFloat(str.(float64), 'G', -1, 64)
}
next.Value = str.(string)
next.Next = blankNode()
prevnode = next
next = next.Next
}
prevnode.Next = nil
return orignext, nil
}
// parseMaybeJSON determines if the argument appears to be a JSON array. If
// so, passes to parseJSON; if not, quotes the result and returns a single
// node.
func parseMaybeJSON(rest string) (*Node, error) {
rest = strings.TrimSpace(rest)
if strings.HasPrefix(rest, "[") {
node, err := parseJSON(rest)
if err == nil {
return node, nil
}
}
node := blankNode()
node.Value = rest
return node, nil
}