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Dean Karn
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enhance coersion support (#16)
## [0.9.0] - 2023-06-17 ### Changed - Function signature of custom coercions to allow parsing more complex coercions types such as substr. ### Added - Added new `_substr_[n:n]` COERCE identifier.
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‎CHANGELOG.md‎

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@@ -6,6 +6,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
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## [Unreleased]
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## [0.9.0] - 2023-06-17
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### Changed
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- Function signature of custom coercions to allow parsing more complex coercions types such as substr.
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### Added
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- Added new `_substr_[n:n]` COERCE identifier.
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## [0.8.0] - 2023-06-10
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### Added
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- Ability to register new, remove existing and replace existing COERCE types.
@@ -70,7 +77,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
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### Added
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- Initial conversion from https://github.com/rust-playground/ksql.
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[Unreleased]: https://github.com/go-playground/ksql/compare/v0.8.0...HEAD
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[Unreleased]: https://github.com/go-playground/ksql/compare/v0.9.0...HEAD
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[0.9.0]: https://github.com/go-playground/ksql/compare/v0.8.0...v0.9.0
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[0.8.0]: https://github.com/go-playground/ksql/compare/v0.7.0...v0.8.0
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[0.7.0]: https://github.com/go-playground/ksql/compare/v0.6.1...v0.7.0
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[0.6.1]: https://github.com/go-playground/ksql/compare/v0.6.0...v0.6.1

‎README.md‎

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@@ -1,6 +1,6 @@
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ksql
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=====
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![Project status](https://img.shields.io/badge/version-0.8.0-green.svg)
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![Project status](https://img.shields.io/badge/version-0.9.0-green.svg)
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[![GoDoc](https://godoc.org/github.com/go-playground/ksql?status.svg)](https://pkg.go.dev/github.com/go-playground/ksql)
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![License](https://img.shields.io/dub/l/vibe-d.svg)
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@@ -86,17 +86,19 @@ Expressions support most mathematical and string expressions see below for detai
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| `NULL` | `NULL` | N/A |
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| `Coerce` | `COERCE` | Coerces one data type into another using in combination with 'Identifier'. Syntax is `COERCE <expression> _identifer_`. |
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| `Identifier` | `_identifier_` | Starts and end with an `_` used with 'COERCE' to cast data types, see table below with supported values. You can combine multiple coercions if separated by a COMMA. |
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| `Colon` | `:` | N/A |
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#### COERCE Types
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92-
| Type | Description |
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|---------------|--------------------------------------------------------------------------------------------------------------------------|
94-
| `_datetime_` | This attempts to convert the type into a DateTime. |
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| `_lowercase_` | This converts the text into lowercase. |
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| `_uppercase_` | This converts the text into uppercase. |
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| `_title_` | This converts the text into title case, when the first letter is capitalized but the rest lower cased. |
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| `_string_` | This converts the value into a string and supports the Value's String, Number, Bool, DateTime with nanosecond precision. |
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| `_number_` | This converts the value into an f64 number and supports the Value's Null, String, Number, Bool and DateTime. |
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| Type | Description |
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|-----------------|--------------------------------------------------------------------------------------------------------------------------|
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| `_datetime_` | This attempts to convert the type into a DateTime. |
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| `_lowercase_` | This converts the text into lowercase. |
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| `_uppercase_` | This converts the text into uppercase. |
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| `_title_` | This converts the text into title case, when the first letter is capitalized but the rest lower cased. |
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| `_string_` | This converts the value into a string and supports the Value's String, Number, Bool, DateTime with nanosecond precision. |
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| `_number_` | This converts the value into an f64 number and supports the Value's Null, String, Number, Bool and DateTime. |
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| `_substr_[n:n]` | This allows taking a substring of a string value. this returns Null if no match at specified indices exits. |
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#### License
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‎_examples/custom-coercion/main.go‎

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@@ -29,7 +29,7 @@ func main() {
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// Add custom coercion to the parser.
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// REMEMBER: coercions start and end with an _(underscore).
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guard := ksql.Coercions.Lock()
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guard.T["_star_"] = func(constEligible bool, expression ksql.Expression) (stillConstEligible bool, e ksql.Expression, err error) {
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guard.T["_star_"] = func(_ *ksql.Parser, constEligible bool, expression ksql.Expression) (stillConstEligible bool, e ksql.Expression, err error) {
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return constEligible, &Star{expression}, nil
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}
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guard.Unlock()

‎errors.go‎

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@@ -88,3 +88,21 @@ type ErrUnsupportedCoerce struct {
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func (e ErrUnsupportedCoerce) Error() string {
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return fmt.Sprintf("unsupported type comparison for COERCE: `%s`", e.s)
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}
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// ErrCustom represents a custom error
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type ErrCustom struct {
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S string
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}
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func (e ErrCustom) Error() string {
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return e.S
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}
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// ErrInvalidCoerce represents an invalid Coerce error
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type ErrInvalidCoerce struct {
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Err error
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}
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func (e ErrInvalidCoerce) Error() string {
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return fmt.Sprintf("invalid COERCE: `%s`", e.Err.Error())
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}

‎go.mod‎

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require (
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github.com/araddon/dateparse v0.0.0-20210429162001-6b43995a97de
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github.com/go-playground/itertools v0.1.0
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github.com/go-playground/pkg/v5 v5.20.0
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github.com/stretchr/testify v1.8.1
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github.com/go-playground/pkg/v5 v5.18.0
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github.com/tidwall/gjson v1.14.4
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)
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‎go.sum‎

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github.com/go-playground/itertools v0.1.0/go.mod h1:+TD1WVpn32jr+GpvO+nnb2xXD45SSzt18Fo/C0y9PJE=
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github.com/go-playground/pkg/v5 v5.18.0 h1:qnYuhWhwLdWj6ut9jagFjaiUI6PZTo3SafR5Um9w214=
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github.com/go-playground/pkg/v5 v5.18.0/go.mod h1:eT8XZeFHnqZkfkpkbI8ayjfCw9GohV2/j8STbVmoR6s=
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github.com/go-playground/pkg/v5 v5.20.0 h1:cSiC5f8KAvWHCV2vmYyNFgIZE6Fvx3WJO5Uw+pXOdxw=
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github.com/go-playground/pkg/v5 v5.20.0/go.mod h1:eT8XZeFHnqZkfkpkbI8ayjfCw9GohV2/j8STbVmoR6s=
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github.com/mattn/go-runewidth v0.0.10/go.mod h1:RAqKPSqVFrSLVXbA8x7dzmKdmGzieGRCM46jaSJTDAk=
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github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
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github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=

‎lexer.go‎

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// Token represents a lexed token
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type Token struct {
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start uint32
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len uint16
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kind TokenKind
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Start uint32
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Len uint16
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Kind TokenKind
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}
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// LexerResult represents a token lexed result
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CloseParen
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Coerce
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Identifier
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Colon
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)
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// / Try to lex a single token from the input stream.
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result = LexerResult{kind: Comma, len: 1}
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case '!':
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result = LexerResult{kind: Not, len: 1}
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case ':':
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result = LexerResult{kind: Colon, len: 1}
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case '"', '\'':
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result, err = tokenizeString(data, b)
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case '.':
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169172
func tokenizeIdentifier(data []byte) (result LexerResult, err error) {
170173
end := takeWhile(data, func(b byte) bool {
171-
return !isWhitespace(b) && b != ')' && b != ']' && b != ','
174+
return !isWhitespace(b) && b != ')' && b != '[' && b != ']' && b != ','
172175
})
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// identifier must start and end with underscore
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// identifier must Start and end with underscore
174177
if end > 0 && data[end-1] == '_' {
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result = LexerResult{
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kind: Identifier,
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})
352355
}
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// NewTokenizer creates a new tokenizer for use
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// NewTokenizer creates a new Tokenizer for use
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func NewTokenizer(src []byte) *Tokenizer {
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return &Tokenizer{
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pos: 0,
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379382
return optionext.Some(resultext.Err[Token, error](err))
380383
}
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token := Token{
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start: t.pos,
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len: result.len,
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kind: result.kind,
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Start: t.pos,
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Len: result.len,
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Kind: result.kind,
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}
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t.chomp(result.len)
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return optionext.Some(resultext.Ok[Token, error](token))

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