chore: add mercury

rsql/ast.go

@@ -0,0 +1,255 @@
+package rsql
+
+import (
+	"bytes"
+	"strings"
+)
+
+// Node is the smallest unit of ast
+type Node interface {
+	TokenLiteral() string
+	String() string
+}
+
+// Statement is a executable tree
+type Statement interface {
+	Node
+	statementNode()
+}
+
+// Expression is a portion of tree
+type Expression interface {
+	Node
+	expressionNode()
+}
+
+// Identifier is a variable name
+type Identifier struct {
+	Token Token
+	Value string
+}
+
+func (i *Identifier) expressionNode() {}
+
+// TokenLiteral returns the literal value of a token
+func (i *Identifier) TokenLiteral() string { return i.Token.Literal }
+
+// String returns a string representation of value
+func (i *Identifier) String() string { return i.Value }
+
+// Integer is a numeric value
+type Integer struct {
+	Token Token
+	Value int64
+}
+
+func (i *Integer) expressionNode() {}
+
+// TokenLiteral returns the literal value of a token
+func (i *Integer) TokenLiteral() string { return i.Token.Literal }
+
+// String returns a string representation of value
+func (i *Integer) String() string { return i.Token.Literal }
+
+// Float is a floating point value
+type Float struct {
+	Token Token
+	Value float64
+}
+
+func (i *Float) expressionNode() {}
+
+// TokenLiteral returns the literal value of a token
+func (i *Float) TokenLiteral() string { return i.Token.Literal }
+
+// String returns a string representation of value
+func (i *Float) String() string { return i.Token.Literal }
+
+// Bool is a boolean value
+type Bool struct {
+	Token Token
+	Value bool
+}
+
+func (i *Bool) expressionNode() {}
+
+// TokenLiteral returns the literal value of a token
+func (i *Bool) TokenLiteral() string { return i.Token.Literal }
+
+// String returns a string representation of value
+func (i *Bool) String() string { return i.Token.Literal }
+
+// Null is an empty value
+type Null struct {
+	Token Token
+}
+
+func (i *Null) expressionNode() {}
+
+// TokenLiteral returns the literal value of a token
+func (i *Null) TokenLiteral() string { return i.Token.Literal }
+
+// String returns a string representation of value
+func (i *Null) String() string { return i.Token.Literal }
+
+// String is an array of codepoints
+type String struct {
+	Token Token
+	Value string
+}
+
+func (i *String) expressionNode() {}
+
+// TokenLiteral returns the literal value of a token
+func (i *String) TokenLiteral() string { return i.Token.Literal }
+
+// String returns a string representation of value
+func (i *String) String() string {
+	var out bytes.Buffer
+
+	out.WriteRune('"')
+	out.WriteString(i.Value)
+	out.WriteRune('"')
+
+	return out.String()
+}
+
+// Array is an array of tokens
+type Array struct {
+	Token    Token
+	Elements []Expression
+}
+
+func (a *Array) expressionNode() {}
+
+// TokenLiteral returns the literal value of a token
+func (a *Array) TokenLiteral() string { return a.Token.Literal }
+
+// String returns a string representation of value
+func (a *Array) String() string {
+	var out bytes.Buffer
+
+	var elements []string
+	for _, el := range a.Elements {
+		elements = append(elements, el.String())
+	}
+
+	out.WriteRune('(')
+	out.WriteString(strings.Join(elements, ","))
+	out.WriteRune(')')
+
+	return out.String()
+}
+
+// Program is a collection of statements
+type Program struct {
+	Statements []Statement
+	Args       map[string]string
+}
+
+func (p *Program) expressionNode() {}
+
+// TokenLiteral returns the literal value of a token
+func (p *Program) TokenLiteral() string {
+	if len(p.Statements) > 0 {
+		return p.Statements[0].TokenLiteral()
+	}
+	return ""
+}
+
+// String returns a string representation of value
+func (p *Program) String() string {
+	var out bytes.Buffer
+
+	for _, s := range p.Statements {
+		out.WriteString(s.String())
+	}
+	if len(p.Args) > 0 {
+		out.WriteRune('|')
+		for a, b := range p.Args {
+			out.WriteRune(' ')
+			out.WriteString(a)
+			out.WriteRune(':')
+			out.WriteString(b)
+		}
+	}
+	return out.String()
+}
+
+// ExpressionStatement is a collection of expressions
+type ExpressionStatement struct {
+	Token      Token
+	Expression Expression
+}
+
+func (ExpressionStatement) statementNode() {}
+
+// TokenLiteral returns the literal value of a token
+func (e ExpressionStatement) TokenLiteral() string { return e.Token.Literal }
+
+// String returns a string representation of value
+func (e ExpressionStatement) String() string {
+	if e.Expression != nil {
+		return e.Expression.String()
+	}
+
+	return ""
+}
+
+// PrefixExpression is an expression with a preceeding operator
+type PrefixExpression struct {
+	Token    Token
+	Operator string
+	Right    Expression
+}
+
+func (p *PrefixExpression) expressionNode() {}
+
+// TokenLiteral returns the literal value of a token
+func (p *PrefixExpression) TokenLiteral() string { return p.Token.Literal }
+
+// String returns a string representation of value
+func (p *PrefixExpression) String() string {
+	var out bytes.Buffer
+
+	out.WriteRune('(')
+	out.WriteString(p.Operator)
+	out.WriteString(p.Right.String())
+	out.WriteRune(')')
+
+	return out.String()
+}
+
+// InfixExpression is two expressions with a infix operator
+type InfixExpression struct {
+	Token    Token
+	Left     Expression
+	Operator string
+	Right    Expression
+}
+
+func (i *InfixExpression) expressionNode() {}
+
+// TokenLiteral returns the literal value of a token
+func (i *InfixExpression) TokenLiteral() string { return i.Token.Literal }
+
+// String returns a string representation of value
+func (i *InfixExpression) String() string {
+	var out bytes.Buffer
+
+	out.WriteRune('(')
+	if i.Left != nil {
+		out.WriteString(i.Left.String())
+	} else {
+		out.WriteString("nil")
+	}
+	out.WriteString(i.Operator)
+	if i.Right != nil {
+		out.WriteString(i.Right.String())
+	} else {
+		out.WriteString("nil")
+	}
+	out.WriteRune(')')
+
+	return out.String()
+}

rsql/ast_test.go

@@ -0,0 +1,21 @@
+package rsql
+
+import "testing"
+
+func TestString(t *testing.T) {
+	program := &Program{
+		Statements: []Statement {
+			ExpressionStatement{
+				Token: Token{TokEQ, "=="},
+				Expression: &InfixExpression{
+					Token: Token{TokEQ, "=="},
+					Left: &Identifier{Token{TokIdent,"foo"}, "foo"},
+					Operator: "==",
+					Right: &Integer{Token{TokInteger, "5"}, 5},
+				},
+			},
+		},
+	}
+
+	t.Log(program.String())
+}

rsql/dbcolumns.go

@@ -0,0 +1,90 @@
+package rsql
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"unicode"
+)
+
+// DbColumns database model metadata
+type DbColumns struct {
+	Cols  []string
+	index map[string]int
+	Table     string
+	View      string
+}
+
+// Col returns the mapped column names
+func (d *DbColumns) Col(column string) (s string, err error) {
+	idx, ok := d.Index(column)
+	if !ok {
+		err = fmt.Errorf("column not found on table: %v", column)
+		return
+	}
+	return d.Cols[idx], err
+}
+
+// Index returns the column number
+func (d *DbColumns) Index(column string) (idx int, ok bool) {
+	idx, ok = d.index[column]
+	return
+}
+
+// GetDbColumns builds a metadata struct
+func GetDbColumns(o interface{}) *DbColumns {
+	d := DbColumns{}
+	t := reflect.TypeOf(o)
+
+	d.index = make(map[string]int)
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+
+		sp := append(strings.Split(field.Tag.Get("db"), ","), "")
+
+		tag := sp[0]
+
+		json := field.Tag.Get("json")
+		if tag == "" {
+			tag = json
+		}
+
+		graphql := field.Tag.Get("graphql")
+		if tag == "" {
+			tag = graphql
+		}
+
+		if tag == "-" {
+			continue
+		}
+
+		if tag == "" {
+			tag = field.Name
+		}
+
+		d.index[field.Name] = len(d.Cols)
+
+		if _, ok := d.index[tag]; !ok && tag != "" {
+			d.index[tag] = len(d.Cols)
+		}
+		if _, ok := d.index[json]; !ok && json != "" {
+			d.index[json] = len(d.Cols)
+		}
+		if _, ok := d.index[graphql]; !ok && graphql != "" {
+			d.index[graphql] = len(d.Cols)
+		} else if !ok && graphql == "" {
+			a := []rune(field.Name)
+			for i := 0; i < len(a); i++ {
+				if unicode.IsLower(a[i]) {
+					break
+				}
+				a[i] = unicode.ToLower(a[i])
+			}
+			graphql = string(a)
+			d.index[graphql] = len(d.Cols)
+		}
+
+		d.Cols = append(d.Cols, tag)
+	}
+	return &d
+}

rsql/lexer.go

@@ -0,0 +1,258 @@
+package rsql
+
+import (
+	"unicode"
+	"unicode/utf8"
+)
+
+type Lexer struct {
+	input        string
+	position     int
+	readPosition int
+	rune         rune
+}
+
+// NewLexer returns a new lexing generator
+func NewLexer(in string) *Lexer {
+	l := &Lexer{input: in}
+	l.readRune()
+	return l
+}
+
+// NextToken returns the next token from lexer
+func (l *Lexer) NextToken() Token {
+	var tok Token
+
+	l.skipSpace()
+
+	switch l.rune {
+	case '-':
+		l.readRune()
+		if isNumber(l.rune) {
+			var isFloat bool
+			tok.Literal, isFloat = l.readNumber()
+			if isFloat {
+				tok.Type = TokFloat
+			} else {
+				tok.Type = TokInteger
+			}
+
+		} else if isLetter(l.rune) {
+			tok.Literal = l.readIdentifier()
+			tok.Type = lookupIdent(tok.Literal)
+
+		} else {
+			tok = newToken(TokIllegal, l.rune)
+			return tok
+		}
+
+		tok.Literal = "-" + tok.Literal
+		return tok
+	case '=':
+		r := l.peekRune()
+		if r == '=' {
+			r := l.rune
+			l.readRune()
+			tok.Type, tok.Literal = TokEQ, string(r)+string(l.rune)
+		} else if isLetter(r) {
+			tok = l.readFIQL()
+
+			return tok
+		} else {
+			tok = newToken(TokIllegal, l.rune)
+		}
+	case ';':
+		tok = newToken(TokAND, l.rune)
+	case ',':
+		tok = newToken(TokOR, l.rune)
+	case ')':
+		tok = newToken(TokRParen, l.rune)
+	case '(':
+		tok = newToken(TokLParen, l.rune)
+	case ']':
+		tok = newToken(TokRBracket, l.rune)
+	case '[':
+		tok = newToken(TokLBracket, l.rune)
+	case '~':
+		tok = newToken(TokLIKE, l.rune)
+	case '!':
+		if l.peekRune() == '=' {
+			r := l.rune
+			l.readRune()
+			tok.Type, tok.Literal = TokNEQ, string(r)+string(l.rune)
+		} else if l.peekRune() == '~' {
+			r := l.rune
+			l.readRune()
+			tok.Type, tok.Literal = TokNLIKE, string(r)+string(l.rune)
+		} else {
+			tok = newToken(TokIllegal, l.rune)
+			return tok
+		}
+	case '<':
+		if l.peekRune() == '=' {
+			r := l.rune
+			l.readRune()
+			tok.Type, tok.Literal = TokLE, string(r)+string(l.rune)
+		} else {
+			tok = newToken(TokLT, l.rune)
+		}
+	case '>':
+		if l.peekRune() == '=' {
+			r := l.rune
+			l.readRune()
+			tok.Type, tok.Literal = TokGE, string(r)+string(l.rune)
+		} else {
+			tok = newToken(TokGT, l.rune)
+		}
+	case '"', '\'':
+		tok.Type = TokString
+		tok.Literal = l.readString(l.rune)
+	case 0:
+		tok.Type, tok.Literal = TokEOF, ""
+	default:
+		if isNumber(l.rune) {
+			var isFloat bool
+			tok.Literal, isFloat = l.readNumber()
+			if isFloat {
+				tok.Type = TokFloat
+			} else {
+				tok.Type = TokInteger
+			}
+
+		} else if isLetter(l.rune) {
+			tok.Literal = l.readIdentifier()
+			tok.Type = lookupIdent(tok.Literal)
+
+		} else {
+			tok = newToken(TokIllegal, l.rune)
+			return tok
+		}
+
+		return tok
+	}
+
+	l.readRune()
+	return tok
+}
+
+func (l *Lexer) readRune() {
+	var size int
+	if l.readPosition >= len(l.input) {
+		l.rune = 0
+	} else {
+		l.rune, size = utf8.DecodeRuneInString(l.input[l.readPosition:])
+	}
+
+	l.position = l.readPosition
+	l.readPosition += size
+}
+func (l *Lexer) peekRune() rune {
+	if l.readPosition >= len(l.input) {
+		return 0
+	}
+	r, _ := utf8.DecodeRuneInString(l.input[l.readPosition:])
+	return r
+}
+
+func (l *Lexer) skipSpace() {
+	for unicode.IsSpace(l.rune) {
+		l.readRune()
+	}
+}
+
+func (l *Lexer) readIdentifier() string {
+	position := l.position
+	if isLetter(l.rune) {
+		l.readRune()
+	}
+
+	for isLetter(l.rune) || isNumber(l.rune) {
+		l.readRune()
+	}
+
+	return l.input[position:l.position]
+}
+
+func (l *Lexer) readNumber() (string, bool) {
+	isFloat := false
+
+	position := l.position
+	for isNumber(l.rune) {
+		if l.rune == '.' {
+			isFloat = true
+		}
+
+		l.readRune()
+	}
+
+	return l.input[position:l.position], isFloat
+}
+func (l *Lexer) readString(st rune) string {
+	position := l.position + 1
+	escape := false
+	for {
+		l.readRune()
+
+		if l.rune == '\\' {
+			escape = true
+
+			continue
+		}
+		if escape {
+			escape = false
+			continue
+		}
+		if l.rune == st || l.rune == 0 {
+			break
+		}
+	}
+
+	return l.input[position:l.position]
+
+}
+func (l *Lexer) readFIQL() Token {
+	l.readRune()
+	s := l.readIdentifier()
+	if l.rune != '=' {
+		return Token{TokIllegal, "=" + s}
+	}
+	l.readRune()
+
+	switch s {
+	case "eq":
+		return Token{TokEQ, "=" + s + "="}
+	case "neq":
+		return Token{TokNEQ, "=" + s + "="}
+	case "gt":
+		return Token{TokGT, "=" + s + "="}
+	case "ge":
+		return Token{TokGE, "=" + s + "="}
+	case "lt":
+		return Token{TokLT, "=" + s + "="}
+	case "le":
+		return Token{TokLE, "=" + s + "="}
+	default:
+		return Token{TokExtend, "=" + s + "="}
+	}
+}
+
+func isLetter(r rune) bool {
+	if unicode.IsSpace(r) {
+		return false
+	}
+	switch r {
+	case '"', '\'', '(', ')', ';', ',', '=', '!', '~', '<', '>', '[', ']':
+		return false
+	}
+	if '0' < r && r < '9' || r == '.' {
+		return false
+	}
+
+	return unicode.IsPrint(r)
+}
+func isNumber(r rune) bool {
+	if '0' <= r && r <= '9' || r == '.' {
+		return true
+	}
+	return false
+}

rsql/lexer_test.go

@@ -0,0 +1,105 @@
+package rsql
+
+import (
+	"testing"
+
+	"github.com/matryer/is"
+)
+
+func TestReservedToken(t *testing.T) {
+	input := `( ) ; , == != ~ < > <= >= [ ]`
+	tests := []struct {
+		expectedType    TokenType
+		expectedLiteral string
+	}{
+		{TokLParen, "("},
+		{TokRParen, ")"},
+		{TokAND, ";"},
+		{TokOR, ","},
+		{TokEQ, "=="},
+		{TokNEQ, "!="},
+		{TokLIKE, "~"},
+		{TokLT, "<"},
+		{TokGT, ">"},
+		{TokLE, "<="},
+		{TokGE, ">="},
+		{TokLBracket, "["},
+		{TokRBracket, "]"},
+	}
+
+	t.Run("Reserved Tokens", func(t *testing.T) {
+		is := is.New(t)
+
+		l := NewLexer(input)
+
+		for _, tt := range tests {
+			tok := l.NextToken()
+			is.Equal(tt.expectedType, tok.Type)
+			is.Equal(tt.expectedLiteral, tok.Literal)
+		}
+	})
+}
+func TestNextToken(t *testing.T) {
+	input := `director=='name\'s';actor=eq="name's";Year=le=2000,Year>=2010;(one <= -1.0, two != true),three=in=(1,2,3);c4==5`
+	tests := []struct {
+		expectedType    TokenType
+		expectedLiteral string
+	}{
+		{TokIdent, `director`},
+		{TokEQ, `==`},
+		{TokString, `name\'s`},
+		{TokAND, `;`},
+		{TokIdent, `actor`},
+		{TokEQ, `=eq=`},
+		{TokString, `name's`},
+		{TokAND, `;`},
+		{TokIdent, "Year"},
+		{TokLE, "=le="},
+		{TokInteger, "2000"},
+		{TokOR, ","},
+		{TokIdent, "Year"},
+		{TokGE, ">="},
+		{TokInteger, "2010"},
+		{TokAND, ";"},
+		{TokLParen, "("},
+		{TokIdent, "one"},
+		{TokLE, "<="},
+		{TokFloat, "-1.0"},
+		{TokOR, ","},
+		{TokIdent, "two"},
+		{TokNEQ, "!="},
+		{TokTRUE, "true"},
+		{TokRParen, ")"},
+		{TokOR, ","},
+		{TokIdent, "three"},
+		{TokExtend, "=in="},
+		{TokLParen, "("},
+		{TokInteger, "1"},
+		{TokOR, ","},
+		{TokInteger, "2"},
+		{TokOR, ","},
+		{TokInteger, "3"},
+		{TokRParen, ")"},
+		{TokAND, ";"},
+		{TokIdent, "c4"},
+		{TokEQ, "=="},
+		{TokInteger, "5"},
+	}
+
+	t.Run("Next Token Parsing", func(t *testing.T) {
+		is := is.New(t)
+
+		l := NewLexer(input)
+
+		c := 0
+		for _, tt := range tests {
+			c++
+			tok := l.NextToken()
+
+			is.Equal(tt.expectedType, tok.Type)
+			is.Equal(tt.expectedLiteral, tok.Literal)
+
+		}
+		is.Equal(c, len(tests))
+	})
+}

rsql/parser.go

@@ -0,0 +1,285 @@
+package rsql
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// Precidence enumerations
+const (
+	_ = iota
+	PrecedenceLowest
+	PrecedenceAND
+	PrecedenceOR
+	PrecedenceCompare
+	PrecedenceHighest
+)
+
+var precidences = map[TokenType]int{
+	TokEQ:   PrecedenceCompare,
+	TokNEQ:  PrecedenceCompare,
+	TokLT:   PrecedenceCompare,
+	TokLE:   PrecedenceCompare,
+	TokGT:   PrecedenceCompare,
+	TokGE:   PrecedenceCompare,
+	TokLIKE: PrecedenceCompare,
+	TokOR:   PrecedenceOR,
+	TokAND:  PrecedenceAND,
+}
+
+type (
+	prefixParseFn func() Expression
+	infixParseFn  func(expression Expression) Expression
+)
+
+// Parser reads lexed values and builds an AST
+type Parser struct {
+	l      *Lexer
+	errors []string
+
+	curToken  Token
+	peekToken Token
+
+	prefixParseFns map[TokenType]prefixParseFn
+	infixParseFns  map[TokenType]infixParseFn
+}
+
+// NewParser returns a parser for a given lexer
+func NewParser(l *Lexer) *Parser {
+	p := &Parser{l: l}
+
+	p.prefixParseFns = make(map[TokenType]prefixParseFn)
+	p.registerPrefix(TokIdent, p.parseIdentifier)
+	p.registerPrefix(TokInteger, p.parseInteger)
+	p.registerPrefix(TokFloat, p.parseFloat)
+	p.registerPrefix(TokTRUE, p.parseBool)
+	p.registerPrefix(TokFALSE, p.parseBool)
+	p.registerPrefix(TokNULL, p.parseNull)
+	p.registerPrefix(TokString, p.parseString)
+	p.registerPrefix(TokLParen, p.parseGroupedExpression)
+	p.registerPrefix(TokLBracket, p.parseArray)
+
+	p.infixParseFns = make(map[TokenType]infixParseFn)
+	p.registerInfix(TokEQ, p.parseInfixExpression)
+	p.registerInfix(TokNEQ, p.parseInfixExpression)
+	p.registerInfix(TokLT, p.parseInfixExpression)
+	p.registerInfix(TokLE, p.parseInfixExpression)
+	p.registerInfix(TokGT, p.parseInfixExpression)
+	p.registerInfix(TokGE, p.parseInfixExpression)
+	p.registerInfix(TokLIKE, p.parseInfixExpression)
+	p.registerInfix(TokAND, p.parseInfixExpression)
+	p.registerInfix(TokOR, p.parseInfixExpression)
+
+	p.nextToken()
+	p.nextToken()
+
+	return p
+}
+
+// DefaultParse sets up a default lex/parse and returns the program
+func DefaultParse(in string) *Program {
+	args := make(map[string]string)
+	in, argstr, ok := strings.Cut(in, "|")
+	if ok {
+		for _, fd := range strings.Fields(argstr) {
+			a, b, _ := strings.Cut(fd, ":")
+			args[a] = b
+		}
+	}
+
+	l := NewLexer(in)
+	p := NewParser(l)
+	return p.ParseProgram(args)
+}
+
+func (p *Parser) registerPrefix(tokenType TokenType, fn prefixParseFn) {
+	p.prefixParseFns[tokenType] = fn
+}
+func (p *Parser) registerInfix(tokenType TokenType, fn infixParseFn) {
+	p.infixParseFns[tokenType] = fn
+}
+
+// Errors returns a list of errors while parsing
+func (p *Parser) Errors() []string {
+	return p.errors
+}
+func (p *Parser) peekError(t TokenType) {
+	msg := fmt.Sprintf("expected next token to be %s, got %s instad",
+		t, p.peekToken.Type)
+	p.errors = append(p.errors, msg)
+}
+
+func (p *Parser) nextToken() {
+	p.curToken = p.peekToken
+	p.peekToken = p.l.NextToken()
+}
+func (p *Parser) curTokenIs(t TokenType) bool {
+	return p.curToken.Type == t
+}
+func (p *Parser) peekTokenIs(t TokenType) bool {
+	return p.peekToken.Type == t
+}
+func (p *Parser) expectPeek(t TokenType) bool {
+	if p.peekTokenIs(t) {
+		p.nextToken()
+		return true
+	}
+	p.peekError(t)
+	return false
+}
+func (p *Parser) peekPrecedence() int {
+	if p, ok := precidences[p.peekToken.Type]; ok {
+		return p
+	}
+	return PrecedenceLowest
+}
+func (p *Parser) curPrecedence() int {
+	if p, ok := precidences[p.curToken.Type]; ok {
+		return p
+	}
+	return PrecedenceLowest
+}
+
+// ParseProgram builds a program AST from lexer
+func (p *Parser) ParseProgram(args map[string]string) *Program {
+	program := &Program{Args: args}
+	program.Statements = []Statement{}
+
+	for p.curToken.Type != TokEOF {
+		stmt := p.parseStatement()
+		if stmt != nil {
+			program.Statements = append(program.Statements, stmt)
+		}
+		p.nextToken()
+	}
+
+	return program
+}
+func (p *Parser) parseStatement() Statement {
+	switch p.curToken.Type {
+	default:
+		return p.parseExpressionStatement()
+	}
+}
+func (p *Parser) parseExpressionStatement() *ExpressionStatement {
+	stmt := &ExpressionStatement{Token: p.curToken}
+	stmt.Expression = p.parseExpression(PrecedenceLowest)
+
+	return stmt
+}
+func (p *Parser) parseExpression(precedence int) Expression {
+	prefix := p.prefixParseFns[p.curToken.Type]
+	if prefix == nil {
+		msg := fmt.Sprintf("no prefix parse function for %s found", p.curToken.Type)
+		p.errors = append(p.errors, msg)
+		return nil
+	}
+	leftExp := prefix()
+
+	for !p.peekTokenIs(TokEOF) && precedence < p.peekPrecedence() {
+		infix := p.infixParseFns[p.peekToken.Type]
+		if infix == nil {
+			return leftExp
+		}
+
+		p.nextToken()
+
+		leftExp = infix(leftExp)
+	}
+
+	return leftExp
+}
+func (p *Parser) parseIdentifier() Expression {
+	return &Identifier{Token: p.curToken, Value: p.curToken.Literal}
+}
+func (p *Parser) parseInteger() Expression {
+	lit := &Integer{Token: p.curToken}
+
+	value, err := strconv.ParseInt(p.curToken.Literal, 0, 64)
+	if err != nil {
+		msg := fmt.Sprintf("could not parse %q as integer", p.curToken.Literal)
+		p.errors = append(p.errors, msg)
+		return nil
+	}
+
+	lit.Value = value
+	return lit
+}
+func (p *Parser) parseFloat() Expression {
+	lit := &Float{Token: p.curToken}
+
+	value, err := strconv.ParseFloat(p.curToken.Literal, 64)
+	if err != nil {
+		msg := fmt.Sprintf("could not parse %q as float", p.curToken.Literal)
+		p.errors = append(p.errors, msg)
+		return nil
+	}
+
+	lit.Value = value
+	return lit
+}
+func (p *Parser) parseBool() Expression {
+	return &Bool{Token: p.curToken, Value: p.curTokenIs(TokTRUE)}
+}
+func (p *Parser) parseString() Expression {
+	s := p.curToken.Literal
+	s = strings.Replace(s, `\'`, `'`, -1)
+	s = strings.Replace(s, `\"`, `"`, -1)
+
+	return &String{Token: p.curToken, Value: s}
+}
+func (p *Parser) parseNull() Expression {
+	return &Null{Token: p.curToken}
+}
+func (p *Parser) parseArray() Expression {
+	array := &Array{Token: p.curToken}
+	array.Elements = p.parseExpressionList(TokRBracket)
+	return array
+}
+func (p *Parser) parseExpressionList(end TokenType) []Expression {
+	var list []Expression
+
+	if p.peekTokenIs(end) {
+		p.nextToken()
+		return list
+	}
+
+	p.nextToken()
+	list = append(list, p.parseExpression(PrecedenceHighest))
+	for p.peekTokenIs(TokOR) {
+		p.nextToken()
+		p.nextToken()
+		list = append(list, p.parseExpression(PrecedenceHighest))
+	}
+
+	if !p.expectPeek(end) {
+		return nil
+	}
+
+	return list
+}
+func (p *Parser) parseInfixExpression(left Expression) Expression {
+	expression := &InfixExpression{
+		Token:    p.curToken,
+		Left:     left,
+		Operator: p.curToken.Literal,
+	}
+
+	precidence := p.curPrecedence()
+	p.nextToken()
+	expression.Right = p.parseExpression(precidence)
+
+	return expression
+}
+func (p *Parser) parseGroupedExpression() Expression {
+	p.nextToken()
+
+	exp := p.parseExpression(PrecedenceLowest)
+
+	if !p.expectPeek(TokRParen) {
+		return nil
+	}
+
+	return exp
+}

rsql/parser_test.go

@@ -0,0 +1,309 @@
+package rsql
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/matryer/is"
+)
+
+func typeOf(t any) string { return fmt.Sprintf("%T", t) }
+
+func TestIdentifierExpression(t *testing.T) {
+	input := `foobar`
+
+	t.Run("Identifier Expressions", func(t *testing.T) {
+		is := is.New(t)
+
+		l := NewLexer(input)
+		p := NewParser(l)
+
+		program := p.ParseProgram(nil)
+		checkParserErrors(t, p)
+
+		is.Equal(len(program.Statements), 1)
+		// if len(program.Statements) != 1 {
+		// 	t.Fatalf("program has not envough statements. got=%d", len(program.Statements))
+		// }
+	})
+}
+
+func TestIntegerExpression(t *testing.T) {
+	input := `5`
+
+	t.Run("IntegerExpression", func(t *testing.T) {
+		is := is.New(t)
+
+		l := NewLexer(input)
+		p := NewParser(l)
+
+		program := p.ParseProgram(nil)
+		checkParserErrors(t, p)
+
+		is.Equal(len(program.Statements), 1)
+		// if len(program.Statements) != 1 {
+		// 	t.Fatalf("program has not enough statements. got=%d", len(program.Statements))
+		// }
+
+		stmt, ok := program.Statements[0].(*ExpressionStatement)
+		is.Equal(typeOf(program.Statements[0]), typeOf(&ExpressionStatement{}))
+		is.True(ok)
+		// if !ok {
+		// 	t.Fatalf("program.Statements[0] is not ExpressionStatement got=%T",
+		// 		program.Statements[0])
+		// }
+
+		literal, ok := stmt.Expression.(*Integer)
+		is.Equal(typeOf(literal), typeOf(&Integer{}))
+		is.True(ok)
+		// if !ok {
+		// 	t.Fatalf("stmt.Expression is not Integer got=%T",
+		// 		stmt.Expression)
+		// }
+
+		is.Equal(literal.Value, int64(5))
+		// if literal.Value != 5 {
+		// 	t.Errorf("literal.Value not %d. got=%d", 5, literal.Value)
+		// }
+
+		is.Equal(literal.TokenLiteral(), "5")
+		// if literal.TokenLiteral() != "5" {
+		// 	t.Errorf("literal.TokenLiteral not %v. got=%v", "5", literal.TokenLiteral())
+		// }
+	})
+}
+
+func TestInfixExpression(t *testing.T) {
+	tests := []struct {
+		input    string
+		left     string
+		operator string
+		right    int64
+	}{
+		{"foo == 1", "foo", "==", 1},
+		{"bar >  2", "bar", ">", 2},
+		{"bin <  3", "bin", "<", 3},
+		{"baz != 4", "baz", "!=", 4},
+		{"buf >= 5", "buf", ">=", 5},
+		{"goz <= 6", "goz", "<=", 6},
+	}
+	t.Run("Infix Expressions", func(t *testing.T) {
+		is := is.New(t)
+
+		for _, tt := range tests {
+			l := NewLexer(tt.input)
+			p := NewParser(l)
+			program := p.ParseProgram(nil)
+			checkParserErrors(t, p)
+
+			is.Equal(len(program.Statements), 1)
+			// if len(program.Statements) != 1 {
+			// 	t.Fatalf("program has not envough statements. got=%d", len(program.Statements))
+			// }
+
+			stmt, ok := program.Statements[0].(*ExpressionStatement)
+			is.Equal(typeOf(stmt), typeOf(&ExpressionStatement{}))
+			is.True(ok)
+			// if !ok {
+			// 	t.Fatalf("program.Statements[0] is not ExpressionStatement got=%T",
+			// 		program.Statements[0])
+			// }
+
+			exp, ok := stmt.Expression.(*InfixExpression)
+			is.Equal(typeOf(exp), typeOf(&InfixExpression{}))
+			is.True(ok)
+			// if !ok {
+			// 	t.Fatalf("stmt.Expression is not InfixExpression got=%T",
+			// 		stmt.Expression)
+			// }
+
+			if !testIdentifier(t, exp.Left, tt.left) {
+				return
+			}
+
+			is.Equal(exp.Operator, tt.operator)
+			// if exp.Operator != tt.operator {
+			// 	t.Fatalf("exp.Operator is not '%v'. got '%v'", tt.operator, exp.Operator)
+			// }
+
+			if testInteger(t, exp.Right, tt.right) {
+				return
+			}
+		}
+	})
+}
+
+func TestOperatorPrecedenceParsing(t *testing.T) {
+	tests := []struct {
+		input  string
+		expect string
+	}{
+		{
+			"foo == 1; bar == 2.0",
+			"((foo==1);(bar==2.0))",
+		},
+		{
+			`director=='name\'s';actor=eq="name\'s";Year=le=2000,Year>=2010;one <= -1.0, two != true`,
+			`((((director=="name's");(actor=eq="name's"));((Year=le=2000),(Year>=2010)));((one<=-1.0),(two!=true)))`,
+		},
+	}
+	t.Run("Operator Precidence Parsing", func(t *testing.T) {
+		is := is.New(t)
+
+		for _, tt := range tests {
+			l := NewLexer(tt.input)
+			p := NewParser(l)
+			program := p.ParseProgram(nil)
+			checkParserErrors(t, p)
+
+			actual := program.String()
+			is.Equal(actual, tt.expect)
+			// if actual != tt.expect {
+			// 	t.Errorf("expcected=%q, got=%q", tt.expect, actual)
+			// }
+		}
+	})
+}
+
+func TestParsingArray(t *testing.T) {
+	input := "[1, 2.1, true, null]"
+
+	l := NewLexer(input)
+	p := NewParser(l)
+	program := p.ParseProgram(nil)
+	checkParserErrors(t, p)
+
+	if len(program.Statements) != 1 {
+		t.Fatalf("program has not enough statements. got=%d", len(program.Statements))
+	}
+
+	stmt, ok := program.Statements[0].(*ExpressionStatement)
+	if !ok {
+		t.Fatalf("program.Statements[0] is not ExpressionStatement got=%T",
+			program.Statements[0])
+	}
+
+	array, ok := stmt.Expression.(*Array)
+	if !ok {
+		t.Fatalf("stmt.Expression is not Array got=%T",
+			stmt.Expression)
+	}
+
+	if len(array.Elements) != 4 {
+		t.Fatalf("len(array.Elements) not 4. got=%v", len(array.Elements))
+	}
+
+	testInteger(t, array.Elements[0], 1)
+	testFloat(t, array.Elements[1], 2.1)
+	testBool(t, array.Elements[2], true)
+	testNull(t, array.Elements[3])
+}
+
+func checkParserErrors(t *testing.T, p *Parser) {
+	errors := p.Errors()
+	if len(errors) == 0 {
+		return
+	}
+
+	t.Errorf("parser has %d errors", len(errors))
+	for _, msg := range errors {
+		t.Errorf("parser error: %q", msg)
+	}
+	t.FailNow()
+}
+
+func testInteger(t *testing.T, e Expression, value int64) bool {
+	literal, ok := e.(*Integer)
+	if !ok {
+		t.Errorf("stmt.Expression is not Integer got=%T", e)
+		return false
+	}
+
+	if literal.Value != value {
+		t.Errorf("literal.Value not %d. got=%d", value, literal.Value)
+		return false
+	}
+
+	if literal.TokenLiteral() != fmt.Sprintf("%v", value) {
+		t.Errorf("literal.TokenLiteral not %v. got=%v", value, literal.TokenLiteral())
+		return false
+	}
+
+	return true
+}
+func testFloat(t *testing.T, e Expression, value float64) bool {
+	literal, ok := e.(*Float)
+	if !ok {
+		t.Errorf("stmt.Expression is not Float got=%T", e)
+		return false
+	}
+
+	if literal.Value != value {
+		t.Errorf("literal.Value not %f. got=%f", value, literal.Value)
+		return false
+	}
+
+	if literal.TokenLiteral() != fmt.Sprintf("%v", value) {
+		t.Errorf("literal.TokenLiteral not %q. got=%q", fmt.Sprintf("%v", value), literal.TokenLiteral())
+		return false
+	}
+
+	return true
+}
+func testBool(t *testing.T, e Expression, value bool) bool {
+	literal, ok := e.(*Bool)
+	if !ok {
+		t.Errorf("stmt.Expression is not Float got=%T", e)
+		return false
+	}
+
+	if literal.Value != value {
+		t.Errorf("literal.Value not %t. got=%t", value, literal.Value)
+		return false
+	}
+
+	if literal.TokenLiteral() != fmt.Sprintf("%v", value) {
+		t.Errorf("literal.TokenLiteral not %v. got=%v", value, literal.TokenLiteral())
+		return false
+	}
+
+	return true
+}
+func testNull(t *testing.T, e Expression) bool {
+	literal, ok := e.(*Null)
+	if !ok {
+		t.Errorf("stmt.Expression is not Null got=%T", e)
+		return false
+	}
+	if literal.Token.Type != TokNULL {
+		t.Errorf("liternal.Token is not TokNULL got=%T", e)
+		return false
+	}
+
+	return true
+}
+func testIdentifier(t *testing.T, e Expression, value string) bool {
+	literal, ok := e.(*Identifier)
+	if !ok {
+		t.Errorf("stmt.Expression is not Integer got=%T", e)
+		return false
+	}
+
+	if literal.Value != value {
+		t.Errorf("literal.Value not %s. got=%s", value, literal.Value)
+		return false
+	}
+
+	if literal.TokenLiteral() != value {
+		t.Errorf("literal.TokenLiteral not %v. got=%v", value, literal.TokenLiteral())
+		return false
+	}
+
+	return true
+}
+
+func TestReplace(t *testing.T) {
+	is := is.New(t)
+	is.Equal(strings.Replace(`name\'s`, `\'`, `'`, -1), `name's`)
+}

rsql/squirrel/sqlizer.go

@@ -0,0 +1,300 @@
+package squirrel
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/Masterminds/squirrel"
+	"go.sour.is/pkg/rsql"
+)
+
+type dbInfo interface {
+	Col(string) (string, error)
+}
+
+type args map[string]string
+
+func (d *decoder) mkArgs(a args) args {
+	m := make(args, len(a))
+	for k, v := range a {
+		if k == "limit" || k == "offset" {
+			m[k] = v
+			continue
+		}
+
+		var err error
+		if k, err = d.dbInfo.Col(k); err == nil {
+			m[k] = v
+
+		}
+	}
+
+	return m
+}
+
+func (a args) Limit() (uint64, bool) {
+	if a == nil {
+		return 0, false
+	}
+	if v, ok := a["limit"]; ok {
+		i, err := strconv.ParseUint(v, 10, 64)
+		return i, err == nil
+	}
+
+	return 0, false
+}
+func (a args) Offset() (uint64, bool) {
+	if a == nil {
+		return 0, false
+	}
+	if v, ok := a["offset"]; ok {
+		i, err := strconv.ParseUint(v, 10, 64)
+		return i, err == nil
+	}
+
+	return 0, false
+}
+func (a args) Order() []string {
+	var lis []string
+
+	for k, v := range a {
+		if k == "limit" || k == "offset" {
+			continue
+		}
+		lis = append(lis, k+" "+v)
+	}
+
+	return lis
+}
+
+func Query(in string, db dbInfo) (squirrel.Sqlizer, args, error) {
+	d := decoder{dbInfo: db}
+	program := rsql.DefaultParse(in)
+	sql, err := d.decode(program)
+	return sql, d.mkArgs(program.Args), err
+}
+
+type decoder struct {
+	dbInfo dbInfo
+}
+
+func (db *decoder) decode(in *rsql.Program) (squirrel.Sqlizer, error) {
+	switch len(in.Statements) {
+	case 0:
+		return nil, nil
+	case 1:
+		return db.decodeStatement(in.Statements[0])
+	default:
+		a := squirrel.And{}
+		for _, stmt := range in.Statements {
+			d, err := db.decodeStatement(stmt)
+			if d == nil {
+				return nil, err
+			}
+
+			a = append(a, d)
+		}
+		return a, nil
+	}
+}
+func (db *decoder) decodeStatement(in rsql.Statement) (squirrel.Sqlizer, error) {
+	switch s := in.(type) {
+	case *rsql.ExpressionStatement:
+		return db.decodeExpression(s.Expression)
+	}
+	return nil, nil
+}
+func (db *decoder) decodeExpression(in rsql.Expression) (squirrel.Sqlizer, error) {
+	switch e := in.(type) {
+	case *rsql.InfixExpression:
+		return db.decodeInfix(e)
+	}
+	return nil, nil
+}
+func (db *decoder) decodeInfix(in *rsql.InfixExpression) (squirrel.Sqlizer, error) {
+
+	switch in.Token.Type {
+	case rsql.TokAND:
+		a := squirrel.And{}
+		left, err := db.decodeExpression(in.Left)
+		if err != nil {
+			return nil, err
+		}
+
+		switch v := left.(type) {
+		case squirrel.And:
+			for _, el := range v {
+				if el != nil {
+					a = append(a, el)
+				}
+			}
+
+		default:
+			if v != nil {
+				a = append(a, v)
+			}
+		}
+
+		right, err := db.decodeExpression(in.Right)
+		if err != nil {
+			return nil, err
+		}
+
+		switch v := right.(type) {
+		case squirrel.And:
+			for _, el := range v {
+				if el != nil {
+					a = append(a, el)
+				}
+			}
+
+		default:
+			if v != nil {
+				a = append(a, v)
+			}
+		}
+
+		return a, nil
+	case rsql.TokOR:
+		left, err := db.decodeExpression(in.Left)
+		if err != nil {
+			return nil, err
+		}
+		right, err := db.decodeExpression(in.Right)
+		if err != nil {
+			return nil, err
+		}
+
+		return squirrel.Or{left, right}, nil
+	case rsql.TokEQ:
+		col, err := db.dbInfo.Col(in.Left.String())
+		if err != nil {
+			return nil, err
+		}
+		v, err := db.decodeValue(in.Right)
+		if err != nil {
+			return nil, err
+		}
+
+		return squirrel.Eq{col: v}, nil
+	case rsql.TokLIKE:
+		col, err := db.dbInfo.Col(in.Left.String())
+		if err != nil {
+			return nil, err
+		}
+
+		v, err := db.decodeValue(in.Right)
+		if err != nil {
+			return nil, err
+		}
+
+		switch value := v.(type) {
+		case string:
+			return Like{col, strings.Replace(value, "*", "%", -1)}, nil
+		default:
+			return nil, fmt.Errorf("LIKE requires a string value")
+		}
+
+	case rsql.TokNEQ:
+		col, err := db.dbInfo.Col(in.Left.String())
+		if err != nil {
+			return nil, err
+		}
+		v, err := db.decodeValue(in.Right)
+		if err != nil {
+			return nil, err
+		}
+
+		return squirrel.NotEq{col: v}, nil
+	case rsql.TokGT:
+		col, err := db.dbInfo.Col(in.Left.String())
+		if err != nil {
+			return nil, err
+		}
+		v, err := db.decodeValue(in.Right)
+		if err != nil {
+			return nil, err
+		}
+
+		return squirrel.Gt{col: v}, nil
+	case rsql.TokGE:
+		col, err := db.dbInfo.Col(in.Left.String())
+		if err != nil {
+			return nil, err
+		}
+		v, err := db.decodeValue(in.Right)
+		if err != nil {
+			return nil, err
+		}
+
+		return squirrel.GtOrEq{col: v}, nil
+	case rsql.TokLT:
+		col, err := db.dbInfo.Col(in.Left.String())
+		if err != nil {
+			return nil, err
+		}
+		v, err := db.decodeValue(in.Right)
+		if err != nil {
+			return nil, err
+		}
+
+		return squirrel.Lt{col: v}, nil
+	case rsql.TokLE:
+		col, err := db.dbInfo.Col(in.Left.String())
+		if err != nil {
+			return nil, err
+		}
+		v, err := db.decodeValue(in.Right)
+		if err != nil {
+			return nil, err
+		}
+
+		return squirrel.LtOrEq{col: v}, nil
+	default:
+		return nil, nil
+	}
+}
+func (db *decoder) decodeValue(in rsql.Expression) (interface{}, error) {
+	switch v := in.(type) {
+	case *rsql.Array:
+		var values []interface{}
+		for _, el := range v.Elements {
+			v, err := db.decodeValue(el)
+			if err != nil {
+				return nil, err
+			}
+
+			values = append(values, v)
+		}
+
+		return values, nil
+	case *rsql.InfixExpression:
+		return db.decodeInfix(v)
+	case *rsql.Identifier:
+		return v.Value, nil
+	case *rsql.Integer:
+		return v.Value, nil
+	case *rsql.Float:
+		return v.Value, nil
+	case *rsql.String:
+		return v.Value, nil
+	case *rsql.Bool:
+		return v.Value, nil
+	case *rsql.Null:
+		return nil, nil
+	}
+
+	return nil, nil
+}
+
+type Like struct {
+	column string
+	value  string
+}
+
+func (l Like) ToSql() (sql string, args []interface{}, err error) {
+	sql = fmt.Sprintf("%s LIKE(?)", l.column)
+	args = append(args, l.value)
+	return
+}

rsql/squirrel/sqlizer_test.go

@@ -0,0 +1,141 @@
+package squirrel
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/Masterminds/squirrel"
+	"github.com/matryer/is"
+	"go.sour.is/pkg/rsql"
+)
+
+type testTable struct {
+	Foo      string `json:"foo"`
+	Bar      string `json:"bar"`
+	Baz      string `json:"baz"`
+	Director string `json:"director"`
+	Actor    string `json:"actor"`
+	Year     string `json:"year"`
+	Genres   string `json:"genres"`
+	One      string `json:"one"`
+	Two      string `json:"two"`
+	Family   string `json:"family_name"`
+}
+
+func TestQuery(t *testing.T) {
+	d := rsql.GetDbColumns(testTable{})
+	is := is.New(t)
+
+	tests := []struct {
+		input        string
+		expect       squirrel.Sqlizer
+		expectLimit  *uint64
+		expectOffset *uint64
+		expectOrder  []string
+		fail         bool
+	}{
+		{input: "foo==[1, 2, 3]", expect: squirrel.Eq{"foo": []interface{}{1, 2, 3}}},
+		{input: "foo==1,(bar==2;baz==3)", expect: squirrel.Or{squirrel.Eq{"foo": 1}, squirrel.And{squirrel.Eq{"bar": 2}, squirrel.Eq{"baz": 3}}}},
+
+		{input: "foo==1", expect: squirrel.Eq{"foo": 1}},
+		{input: "foo!=1.1", expect: squirrel.NotEq{"foo": 1.1}},
+		{input: "foo==true", expect: squirrel.Eq{"foo": true}},
+		{input: "foo==null", expect: squirrel.Eq{"foo": nil}},
+		{input: "foo>2", expect: squirrel.Gt{"foo": 2}},
+		{input: "foo>=2.1", expect: squirrel.GtOrEq{"foo": 2.1}},
+		{input: "foo<3", expect: squirrel.Lt{"foo": 3}},
+		{input: "foo<=3.1", expect: squirrel.LtOrEq{"foo": 3.1}},
+
+		{input: "foo=eq=1", expect: squirrel.Eq{"foo": 1}},
+		{input: "foo=neq=1.1", expect: squirrel.NotEq{"foo": 1.1}},
+		{input: "foo=gt=2", expect: squirrel.Gt{"foo": 2}},
+		{input: "foo=ge=2.1", expect: squirrel.GtOrEq{"foo": 2.1}},
+		{input: "foo=lt=3", expect: squirrel.Lt{"foo": 3}},
+		{input: "foo=le=3.1", expect: squirrel.LtOrEq{"foo": 3.1}},
+
+		{input: "foo==1;bar==2", expect: squirrel.And{squirrel.Eq{"foo": 1}, squirrel.Eq{"bar": 2}}},
+		{input: "foo==1,bar==2", expect: squirrel.Or{squirrel.Eq{"foo": 1}, squirrel.Eq{"bar": 2}}},
+		{input: "foo==1,bar==2;baz=3", expect: nil},
+		{
+			input: `director=='name\'s';actor=eq="name\'s";Year=le=2000,Year>=2010;one <= -1.0, two != true`,
+			expect: squirrel.And{
+				squirrel.Eq{"director": "name's"},
+				squirrel.Eq{"actor": "name's"},
+				squirrel.Or{
+					squirrel.LtOrEq{"year": 2000},
+					squirrel.GtOrEq{"year": 2010},
+				},
+				squirrel.Or{
+					squirrel.LtOrEq{"one": -1.0},
+					squirrel.NotEq{"two": true},
+				},
+			},
+		},
+		{
+			input: `genres==[sci-fi,action] ; genres==[romance,animated,horror] , director~Que*Tarantino`,
+			expect: squirrel.And{
+				squirrel.Eq{"genres": []interface{}{"sci-fi", "action"}},
+				squirrel.Or{
+					squirrel.Eq{"genres": []interface{}{"romance", "animated", "horror"}},
+					Like{"director", "Que%Tarantino"},
+				},
+			},
+		},
+		{input: "", expect: nil},
+		{input: "family_name==LUNDY", expect: squirrel.Eq{"family_name": "LUNDY"}},
+		{input: "family_name==[1,2,null]", expect: squirrel.Eq{"family_name": []interface{}{1, 2, nil}}},
+		{input: "family_name=LUNDY", expect: nil},
+		{input: "family_name==LUNDY and family_name==SMITH", expect: squirrel.And{squirrel.Eq{"family_name": "LUNDY"}, squirrel.Eq{"family_name": "SMITH"}}},
+		{input: "family_name==LUNDY or family_name==SMITH", expect: squirrel.Or{squirrel.Eq{"family_name": "LUNDY"}, squirrel.Eq{"family_name": "SMITH"}}},
+		{input: "foo==1,family_name=LUNDY;baz==2", expect: nil},
+		{input: "foo ~ bar*", expect: Like{"foo", "bar%"}},
+		{input: "foo ~ [bar*,bin*]", expect: nil, fail: true},
+		{input: "foo==1|limit:10", expect: squirrel.Eq{"foo": 1}, expectLimit: ptr(uint64(10))},
+		{input: "foo==1|offset:2", expect: squirrel.Eq{"foo": 1}, expectOffset: ptr(uint64(2))},
+		{
+			input: "foo>=1|limit:10 offset:2 foo:desc", 
+			expect: squirrel.GtOrEq{"foo": 1}, 
+			expectLimit: ptr(uint64(10)),
+			expectOffset: ptr(uint64(2)),
+			expectOrder: []string{"foo desc"},
+		},
+	}
+
+	for i, tt := range tests {
+		q, a, err := Query(tt.input, d)
+		if !tt.fail && err != nil {
+			t.Error(err)
+		}
+		if q != nil {
+			t.Log(q.ToSql())
+		}
+
+		actual := fmt.Sprintf("%#v", q)
+		expect := fmt.Sprintf("%#v", tt.expect)
+		if expect != actual {
+			t.Errorf("test[%d]: %v\n\tinput and expected are not the same. wanted=%s got=%s", i, tt.input, expect, actual)
+		}
+
+		if limit, ok := a.Limit(); tt.expectLimit != nil {
+			is.True(ok)
+			is.Equal(limit, *tt.expectLimit)
+		} else {
+			is.True(!ok)
+		}
+
+		if offset, ok := a.Offset(); tt.expectOffset != nil {
+			is.True(ok)
+			is.Equal(offset, *tt.expectOffset)
+		} else {
+			is.True(!ok)
+		}
+
+		if order := a.Order(); tt.expectOrder != nil {
+			is.Equal(order, tt.expectOrder)
+		} else {
+			is.Equal(len(order), 0)
+		}
+	}
+}
+
+func ptr[T any](t T) *T { return &t }

rsql/token.go

@@ -0,0 +1,62 @@
+package rsql
+
+// Tokens for RSQL FIQL
+const (
+	TokIllegal = "TokIllegal"
+	TokEOF     = "TokEOF"
+
+	TokIdent   = "TokIdent"
+	TokInteger = "TokInteger"
+	TokString  = "TokString"
+	TokFloat   = "TokFloat"
+	TokExtend  = "TokExtend"
+
+	TokLParen = "("
+	TokRParen = ")"
+
+	TokLBracket = "["
+	TokRBracket = "]"
+
+	TokLIKE = "~"
+	TokNLIKE= "!~"
+	TokNOT  = "!"
+	TokLT   = "<"
+	TokGT   = ">"
+	TokLE   = "<="
+	TokGE   = ">="
+	TokEQ   = "=="
+	TokNEQ  = "!="
+	TokAND  = ";"
+	TokOR   = ","
+
+	TokTRUE  =  "true"
+	TokFALSE = "false"
+	TokNULL  = "null"
+)
+
+var keywords = map[string]TokenType {
+	"true":  TokTRUE,
+	"false": TokFALSE,
+	"null":  TokNULL,
+	"and":   TokAND,
+	"or":    TokOR,
+}
+
+// TokenType is a token enumeration
+type TokenType string
+// Token is a type and literal pair
+type Token struct {
+	Type    TokenType
+	Literal string
+}
+
+func newToken(tokenType TokenType, ch rune) Token {
+	return Token{Type: tokenType, Literal: string(ch)}
+}
+
+func lookupIdent(ident string) TokenType {
+	if tok, ok := keywords[ident]; ok {
+		return tok
+	}
+	return TokIdent
+}