// Resolve ...
func (e *Expr) Resolve(tree map[interface{}]interface{}) (*Expr, error) {
switch e.Type {
case Literal:
return e, nil
case EnvVar:
v := os.Getenv(e.Name)
if v == "" {
return nil, ansi.Errorf("@R{Environment variable} @c{$%s} @R{is not set}", e.Name)
}
return &Expr{Type: Literal, Literal: v}, nil
case Reference:
if _, err := e.Reference.Resolve(tree); err != nil {
return nil, ansi.Errorf("@R{Unable to resolve `}@c{%s}@R{`: %s}", e.Reference, err)
}
return e, nil
case LogicalOr:
if o, err := e.Left.Resolve(tree); err == nil {
return o, nil
}
return e.Right.Resolve(tree)
}
return nil, ansi.Errorf("@R{unknown expression operand type (}@c{%d}@R{)}", e.Type)
}
// Reduce ...
func (e *Expr) Reduce() (*Expr, error) {
var reduce func(*Expr) (*Expr, *Expr, bool)
reduce = func(e *Expr) (*Expr, *Expr, bool) {
switch e.Type {
case Literal:
return e, e, false
case EnvVar:
return e, nil, false
case Reference:
return e, nil, false
case LogicalOr:
l, short, _ := reduce(e.Left)
if short != nil {
return l, short, true
}
r, short, more := reduce(e.Right)
return &Expr{
Type: LogicalOr,
Left: l,
Right: r,
}, short, more
}
return nil, nil, false
}
reduced, short, more := reduce(e)
if more && short != nil {
return reduced, ansi.Errorf("@R{literal} @c{%v} @R{short-circuits expression (}@c{%s}@R{)}", short, e)
}
return reduced, nil
}
// Run ...
func (op *Opcall) Run(ev *Evaluator) (*Response, error) {
was := ev.Here
ev.Here = op.where
r, err := op.op.Run(ev, op.args)
ev.Here = was
if err != nil {
return nil, ansi.Errorf("@m{$.%s}: @R{%s}", op.where, err)
}
return r, nil
}
// Run ...
func (CartesianProductOperator) Run(ev *Evaluator, args []*Expr) (*Response, error) {
DEBUG("running (( cartesian-product ... )) operation at $.%s", ev.Here)
defer DEBUG("done with (( cartesian-product ... )) operation at $%s\n", ev.Here)
var vals [][]string
for i, arg := range args {
v, err := arg.Resolve(ev.Tree)
if err != nil {
DEBUG(" [%d]: resolution failed\n error: %s", i, err)
return nil, err
}
switch v.Type {
case Literal:
DEBUG(" arg[%d]: found string literal '%s'", i, v.Literal)
vals = append(vals, []string{v.Literal.(string)})
case Reference:
DEBUG(" arg[%d]: trying to resolve reference $.%s", i, v.Reference)
s, err := v.Reference.Resolve(ev.Tree)
if err != nil {
DEBUG(" [%d]: resolution failed\n error: %s", i, err)
return nil, ansi.Errorf("Unable to resolve `@m{%s}`: %s", v.Reference, err)
}
switch s.(type) {
case []interface{}:
var strs []string
DEBUG(" [%d]: resolved to a list; verifying", i)
for j, sub := range s.([]interface{}) {
if _, ok := sub.([]interface{}); ok {
DEBUG(" list[%d]: list item is itself a list; error!", j)
return nil, fmt.Errorf("cartesian-product operator can only operate on lists of scalar values")
} else if _, ok := sub.(map[interface{}]interface{}); ok {
DEBUG(" list[%d]: list item is a map; error!", j)
return nil, fmt.Errorf("cartesian-product operator can only operate on lists of scalar values")
}
DEBUG(" list[%d]: list item is a scalar: %v", j, sub)
strs = append(strs, fmt.Sprintf("%v", sub))
}
vals = append(vals, strs)
case map[interface{}]interface{}:
DEBUG(" [%d]: resolved to a map; error!", i)
return nil, fmt.Errorf("cartesian-product operator only accepts arrays and string values")
default:
DEBUG(" [%d]: resolved to a scalar; appending", i)
vals = append(vals, []string{fmt.Sprintf("%v", s)})
}
default:
DEBUG(" arg[%d]: I don't know what to do with '%v'", i, arg)
return nil, fmt.Errorf("cartesian-product operator only accepts key reference arguments")
}
DEBUG("")
}
switch len(args) {
case 0:
DEBUG(" no arguments supplied to (( cartesian-product ... )) operation. oops.")
return nil, ansi.Errorf("no arguments specified to @c{(( cartesian-product ... ))}")
case 1:
DEBUG(" called with only one argument; returning value as-is")
return &Response{
Type: Replace,
Value: vals[0],
}, nil
default:
DEBUG(" called with more than one arguments; combining into a single list of strings")
lst := vals[0]
for _, l := range vals[1:] {
lst = cartesian(lst, l)
}
return &Response{
Type: Replace,
Value: lst,
}, nil
}
}
