miller/pkg/runtime/state.go
John Kerl 9963df4090
Switch to generics (#1763)
* gradually replace list.List with slices

* gradually replace list.List with slices

* more

* more

* more
2025-03-05 08:19:15 -05:00

95 lines
2.9 KiB
Go

// ================================================================
// Tracks everything needed for statement evaluation/assignment in the Miller
// DSL runtimne: current record/context (the latter being NF, NR, etc);
// out-of-stream variables; local-variable stack; etc.
// ================================================================
package runtime
import (
"container/list"
"github.com/johnkerl/miller/v6/pkg/cli"
"github.com/johnkerl/miller/v6/pkg/lib"
"github.com/johnkerl/miller/v6/pkg/mlrval"
"github.com/johnkerl/miller/v6/pkg/types"
)
type State struct {
Inrec *mlrval.Mlrmap
Context *types.Context
Oosvars *mlrval.Mlrmap
FilterExpression *mlrval.Mlrval
Stack *Stack
OutputRecordsAndContexts *list.List // list of *types.RecordAndContext
// For holding "\0".."\9" between where they are set via things like
// '$x =~ "(..)_(...)"', and interpolated via things like '$y = "\2:\1"'.
//
// Each top-level block and user-defined function has its own captures.
//
// For example, in function `f()`, one can do `somevar =~ someregex`, then
// call some function `g()` which also uses `=~`, and then when `g()` returns,
// `f()` will have its "\1", "\2", etc intact.
//
// This is necessary for the stateful semantics of `=~` and "\1", "\2", etc.
// Those are avoided when the user calls `matchx`, which is newer, and
// stateless. However, `=~` exists in the Miller DSL and we must support it.
regexCapturesByFrame [][]string
Options *cli.TOptions
// StrictMode allows for runtime handling of absent-reads and untyped assignments.
StrictMode bool
}
func NewEmptyState(options *cli.TOptions, strictMode bool) *State {
// See lib.MakeEmptyCaptures for context.
regexCapturesByFrame := make([][]string, 1)
regexCapturesByFrame[0] = lib.MakeEmptyCaptures()
oosvars := mlrval.NewMlrmap()
return &State{
Inrec: nil,
Context: nil,
Oosvars: oosvars,
FilterExpression: mlrval.TRUE,
Stack: NewStack(),
regexCapturesByFrame: regexCapturesByFrame,
// OutputRecordsAndContexts is assigned after construction
Options: options,
StrictMode: strictMode,
}
}
func (state *State) Update(
inrec *mlrval.Mlrmap,
context *types.Context,
) {
state.Inrec = inrec
state.Context = context
state.regexCapturesByFrame[0] = lib.MakeEmptyCaptures()
}
func (state *State) SetRegexCaptures(
captures []string,
) {
state.regexCapturesByFrame[0] = lib.CopyStringArray(captures)
}
func (state *State) GetRegexCaptures() []string {
regexCaptures := state.regexCapturesByFrame[0]
return lib.CopyStringArray(regexCaptures)
}
func (state *State) PushRegexCapturesFrame() {
state.regexCapturesByFrame = append([][]string{lib.MakeEmptyCaptures()}, state.regexCapturesByFrame...)
}
func (state *State) PopRegexCapturesFrame() {
state.regexCapturesByFrame = state.regexCapturesByFrame[1:]
}