Switched to expression-based timestamps

cmds/timestamps/input.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"time"
+
+	"github.com/alecthomas/participle/v2"
+	"github.com/alecthomas/participle/v2/lexer"
+)
+
+var basicLexer = lexer.MustSimple([]lexer.SimpleRule{
+	{"Identifier", `[a-zA-Z_][a-zA-Z0-9_]*`},
+	{"Date", `\d{4}-\d{2}-\d{2}`},
+	{"Timestamp", `\d{4}-\d{2}-\d{2}T?\d{2}:\d{2}:\d{2}Z?`},
+	{"Time", `\d{2}:\d{2}:\d{2}Z?`},
+	{"Int", `\d+`},
+	{"Whitespace", `[ ]+`},
+})
+
+var parser = participle.MustBuild[Atom](
+	participle.Lexer(basicLexer),
+	participle.Elide("Whitespace"),
+)
+
+func Parse(expr string) (TimeResult, error) {
+	res, err := parser.ParseString("expr", expr)
+	if err != nil {
+		return nil, err
+	}
+	return res, nil
+}
+
+type TimeResult interface {
+	Time() (time.Time, error)
+	RequiresRefreshing() bool
+}