Add date() and time() with a quoted layout, and let a table with a parent carry a name without a key

2026-09-18 18:05:47 +02:00
parent 7ff817d5ae
commit 289d5edc31
3 changed files with 135 additions and 14 deletions
@@ -7,6 +7,7 @@ import (
 	"math"
 	"strconv"
 	"strings"
+	"time"
 	"unicode"
 )

@@ -60,6 +61,8 @@ var builtins = map[string]builtin{
 		cc := a[0]
 		return func(s *session, _ string, _ []string) string { return iban(s, cc) }
 	}},
+	"date":      {arity: 3, check: dateArgs, prep: datePrep},
+	"time":      {arity: 1, check: timeArg, prep: timePrep},
 	"calc":      {arity: -1, check: checkCalc, prep: calcPrep, operands: calcOperands},
 	"lowercase": {arity: 1, check: transformArg, prep: transformPrep(strings.ToLower), operands: transformOperand},
 	"uppercase": {arity: 1, check: transformArg, prep: transformPrep(strings.ToUpper), operands: transformOperand},
@@ -466,3 +469,87 @@ func iban(r rng, cc string) string {
 	feed(0)
 	return fmt.Sprintf("%s%02d%s", cc, 98-rem, bban)
 }
+
+const dayLayout = "2006-01-02"
+
+// The two instants a layout is proved against: alike in nothing, so a layout that
+// formats them alike names no field, and one that tells their days apart at the same
+// clock names a date field.
+var (
+	layoutProbe  = time.Date(2001, 2, 3, 4, 5, 6, 0, time.UTC)
+	layoutProbe2 = time.Date(2010, 11, 12, 13, 14, 15, 0, time.UTC)
+	layoutDay    = time.Date(2010, 11, 12, 4, 5, 6, 0, time.UTC)
+)
+
+// layoutArg is the Go layout a quoted arg holds; unquoted, it is refused naming the
+// quoted spelling, since a layout may carry the comma that splits args.
+func layoutArg(a string) (string, error) {
+	if len(a) < 2 || a[0] != '\'' || a[len(a)-1] != '\'' {
+		return "", fmt.Errorf("layout %s is not quoted; write '%s'", a, strings.Trim(a, "'"))
+	}
+	layout := a[1 : len(a)-1]
+	if layoutProbe.Format(layout) == layoutProbe2.Format(layout) {
+		return "", fmt.Errorf("layout '%s' names no field, so it is the constant %q; write it as text", layout, layout)
+	}
+	return layout, nil
+}
+
+// layoutOf is layoutArg for an arg a check already validated.
+func layoutOf(a string) string {
+	layout, err := layoutArg(a)
+	if err != nil {
+		panic(fmt.Sprintf("fejkdata: builtin arg %q reached prep unvalidated: %v", a, err))
+	}
+	return layout
+}
+
+func dateArgs(_ map[string]node, a []string) error {
+	from, err := time.Parse(dayLayout, a[0])
+	if err != nil {
+		return fmt.Errorf("date(from,to,layout): from %q is not a YYYY-MM-DD date", a[0])
+	}
+	to, err := time.Parse(dayLayout, a[1])
+	if err != nil {
+		return fmt.Errorf("date(from,to,layout): to %q is not a YYYY-MM-DD date", a[1])
+	}
+	if !from.Before(to) {
+		return fmt.Errorf("date(from,to,layout): from %s is not before to %s", a[0], a[1])
+	}
+	_, err = layoutArg(a[2])
+	return err
+}
+
+func timeArg(_ map[string]node, a []string) error {
+	layout, err := layoutArg(a[0])
+	if err != nil {
+		return err
+	}
+	if layoutProbe.Format(layout) != layoutDay.Format(layout) {
+		return fmt.Errorf("time(layout): '%s' names a date field; write date(from,to,layout)", layout)
+	}
+	return nil
+}
+
+// datePrep draws a second in [from 00:00:00, to 23:59:59] UTC; the span is counted
+// in seconds, since a Duration overflows past 292 years.
+func datePrep(a []string) callFn {
+	from, err := time.Parse(dayLayout, a[0])
+	if err != nil {
+		panic(fmt.Sprintf("fejkdata: builtin arg %q reached prep unvalidated: %v", a[0], err))
+	}
+	to, err := time.Parse(dayLayout, a[1])
+	if err != nil {
+		panic(fmt.Sprintf("fejkdata: builtin arg %q reached prep unvalidated: %v", a[1], err))
+	}
+	layout, start, span := layoutOf(a[2]), from.Unix(), int(to.Unix()-from.Unix())+86400
+	return func(s *session, _ string, _ []string) string {
+		return time.Unix(start+int64(s.IntN(span)), 0).UTC().Format(layout)
+	}
+}
+
+func timePrep(a []string) callFn {
+	layout := layoutOf(a[0])
+	return func(s *session, _ string, _ []string) string {
+		return time.Unix(int64(s.IntN(86400)), 0).UTC().Format(layout)
+	}
+}
@@ -222,8 +222,8 @@ func (t *table) bindOptions(o tableOptionValues) error {
 		}
 		*opt.into = i
 	}
-	if t.name >= 0 && t.key < 0 {
-		return fmt.Errorf("name selects a row as a key does, and lists the rows it matches by their keys, so it needs a key column; add key")
+	if t.name >= 0 && t.key < 0 && t.parent < 0 {
+		return fmt.Errorf("name selects a row as a key does, and lists the rows it matches by their keys, so it needs a key column, or a parent inside which each name is one row; add key")
 	}
 	if err := t.indexKeys(); err != nil {
 		return err
@@ -231,9 +231,18 @@ func (t *table) bindOptions(o tableOptionValues) error {
 	return t.sumWeights()
 }

-// indexKeys proves every key names one row, and keeps the index a link is proved by.
+// indexKeys proves every key names one row, and keeps the index a link is proved by;
+// without a key, a name names one row inside its parent.
 func (t *table) indexKeys() error {
 	if t.key < 0 {
+		inside := make(map[string]int, t.rows())
+		for r := 0; r < t.rows() && t.name >= 0; r++ {
+			k := t.cell(r, t.parent) + "\t" + t.cell(r, t.name)
+			if first, dup := inside[k]; dup {
+				return fmt.Errorf("%s line %d: name %q repeats line %d inside %s %q; a name selects one row inside its parent", t.file, r+2, t.cell(r, t.name), first+2, t.columns[t.parent], t.cell(r, t.parent))
+			}
+			inside[k] = r
+		}
 		return nil
 	}
 	t.byKey = make(map[string]int, t.rows())
@@ -488,8 +497,8 @@ func (t *table) under(r int, a *table, pr int) bool {
 // find is the row a selector names: by key first, then by name, where a name
 // naming several rows resolves inside the ancestors pinned in d.
 func (t *table) find(sel string, d *draws) (int, error) {
-	if t.key < 0 {
-		return 0, fmt.Errorf("%s has no key column to select a row by", t.category)
+	if t.key < 0 && t.name < 0 {
+		return 0, fmt.Errorf("%s has no key or name column to select a row by", t.category)
 	}
 	if r, ok := t.byKey[sel]; ok {
 		return r, nil
@@ -506,7 +515,14 @@ func (t *table) find(sel string, d *draws) (int, error) {
 	}
 	keys := make([]string, len(rows))
 	for i, r := range rows {
-		keys[i] = t.cell(r, t.key)
+		if t.key < 0 {
+			keys[i] = t.selectorSpelling(r)
+		} else {
+			keys[i] = t.cell(r, t.key)
+		}
+	}
+	if t.key < 0 {
+		return 0, fmt.Errorf("%q names %d rows of %s; select it inside its %s, one of %v", sel, len(rows), t.category, t.parentT.category, keys)
 	}
 	inside := ""
 	if t.parentT != nil {
@@ -515,7 +531,14 @@ func (t *table) find(sel string, d *draws) (int, error) {
 	return 0, fmt.Errorf("%q names %d rows of %s; select one by key, one of %v%s", sel, len(rows), t.category, keys, inside)
 }

-// selectorSpelling is how a path writes a selected row, for messages.
+// selectorSpelling is how a path writes a selected row, for messages: by key, or
+// by name inside its parent's row.
 func (t *table) selectorSpelling(r int) string {
-	return t.category + "[" + t.cell(r, t.key) + "]"
+	switch {
+	case t.key >= 0:
+		return t.category + "[" + t.cell(r, t.key) + "]"
+	case t.name >= 0:
+		return t.parentT.selectorSpelling(t.parentRow(r)) + "." + t.category + "[" + t.cell(r, t.name) + "]"
+	}
+	return fmt.Sprintf("%s line %d", t.file, r+2)
 }
@@ -88,17 +88,28 @@ func funcCall(body string) (name string, args []string, ok bool) {
 	return body[:lp], splitArgs(body[lp+1 : len(body)-1]), true
 }

-// splitArgs parses a function arg list: comma-separated outside a selector,
-// trimmed; empty -> none.
+// splitArgs parses a function arg list: comma-separated outside a selector or a
+// quoted layout, trimmed; empty -> none.
 func splitArgs(s string) []string {
 	if strings.TrimSpace(s) == "" {
 		return nil
 	}
-	args := splitOutside(s, ',')
-	for i := range args {
-		args[i] = strings.TrimSpace(args[i])
+	var args []string
+	depth, quoted, start := 0, false, 0
+	for i := 0; i < len(s); i++ {
+		switch c := s[i]; {
+		case c == '\'':
+			quoted = !quoted
+		case quoted:
+		case c == '[':
+			depth++
+		case c == ']' && depth > 0:
+			depth--
+		case c == ',' && depth == 0:
+			args, start = append(args, strings.TrimSpace(s[start:i])), i+1
+		}
 	}
-	return args
+	return append(args, strings.TrimSpace(s[start:]))
 }

 // checkFunc validates a function token at compile time: well-formed, naming a