48 lines
1.7 KiB
Go
48 lines
1.7 KiB
Go
package grammar
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import (
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"fmt"
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"strings"
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)
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// reservedInIdentifier is what an identifier may not contain: a dot
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// separates the segments of a path, '|' the arms of a token, '(' opens a function
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// call, braces delimit the token, '/' starts a reference, and brackets and a quote
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// open a JSON value. An identifier carrying one is rejected where it is authored.
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const reservedInIdentifier = ".|({}/[]\""
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var reservedList = strings.Join(strings.Split(reservedInIdentifier, ""), " ")
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// An identifier names a folder, category, field, column or bound name. CheckIdentifier rejects one
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// that the dot path, {token} and JSON grammars cannot spell, or that a struct tag cannot read.
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func CheckIdentifier(name string) error {
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if name == "" {
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return fmt.Errorf("%q is empty, which is not a path segment, so List never offers it", name)
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}
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if name == "-" {
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return fmt.Errorf(`%q is reserved: the struct tag fake:"-" leaves a field unfilled, so no tag could read it; rename it`, name)
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}
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if strings.Contains(name, AsWord) {
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return fmt.Errorf("%q contains %q, which a token reads as binding a name; rename it", name, AsWord)
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}
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if i := strings.IndexAny(name, reservedInIdentifier); i >= 0 {
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return fmt.Errorf("%q contains %q; a name may not use %s, which the dot path, {token} and JSON grammars reserve",
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name, name[i:i+1], reservedList)
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}
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return nil
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}
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// CheckPathIdentifiers rejects a dotted path with a segment no identifier may be.
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func CheckPathIdentifiers(path string) error {
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segs, err := SplitPath(path)
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if err != nil {
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return err
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}
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for _, seg := range IdentifierSegments(segs) {
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if err := CheckIdentifier(seg); err != nil {
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return fmt.Errorf("path %w", err)
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}
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}
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return nil
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}
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