fix #49 regular expressions, operator match and docs

docs/Regex.md

@@ -0,0 +1,91 @@
+# Regular expressions
+
+In lyng, you create regular expressions using class `Regex` or `String.re` methods:
+
+    assert( "\d*".re is Regex )
+    assert( Regex("\d*") is Regex )
+    >>> void
+
+We plan to add slash syntax at some point.
+
+To check that some string matches as whole to some regex:
+
+    assert( "123".matches("\d{3}".re) )
+    assert( !"123".matches("\d{4}".re) )
+    assert( !"1234".matches("\d".re) )
+    >>> void
+
+To check that _part of the string_ matches some regular expession, use _match operator_ `=~` just like in Ruby, and its
+counterpart, _not match_ operator `!~`:
+
+    assert( "abc123def" =~ "\d\d\d".re )
+    assert( "abc" !~ "\d\d\d".re )
+    >>> void
+
+When you need to find groups, and more detailed match information, use `Regex.find`:
+
+    val result = Regex("abc(\d)(\d)(\d)").find( "bad456 good abc123")
+    assert( result  != null )
+    assertEquals( 12 .. 17, result.range )
+    assertEquals( "abc123", result[0] )
+    assertEquals( "1", result[1] )
+    assertEquals( "2", result[2] )
+    assertEquals( "3", result[3] )
+    >>> void
+
+Note that the object `RegexMatch`, returned by [Regex.find], behaves much like in many other languages: it provides the
+index range and groups matches as indexes.
+
+Match operator actually also provides `RegexMatch` in `$~` reserved variable (borrowed from Ruby too):
+
+    assert( "bad456 good abc123" =~ "abc(\d)(\d)(\d)".re )
+    assertEquals( 12 .. 17, $~.range )
+    assertEquals( "abc123", $~[0] )
+    assertEquals( "1", $~[1] )
+    assertEquals( "2", $~[2] )
+    assertEquals( "3", $~[3] )
+    >>> void
+
+This is often more readable than calling `find`.
+
+Note that `=~` and `!~` operators against strings and regular expressions are commutative, e.g. regular expression and a
+string can be either left or right operator, but not both:
+
+    assert( "abc" =~ "\wc".re )
+    assert( "abc" !~ "\w1c".re )
+    assert( "a\wc".re =~ "abcd" )
+    assert( "a[a-z]c".re !~ "a2cd" )
+    >>> void
+
+Also, string indexing is Regex-aware, and works like `Regex.find` (_not findall!_):
+
+    assert( "cd" == "abcdef"[ "c.".re ].value )
+    >>> void
+
+
+# Regex class reference
+
+| name         | description                         | notes |
+|--------------|-------------------------------------|-------|
+| matches(str) | true if the whole `str` matches     |       |
+| find(str)    | find first match in `str` or null   | (1)   |
+| findAll(str) | find all matches in `str` as [List] | (1)   |
+
+(1)
+:: See `RegexMatch` class description below
+
+# RegexMatch
+
+| name  | description                               | notes |
+|-------|-------------------------------------------|-------|
+| range | the [Range] of the match in source string |       |
+| value | the value that matches                    |       |
+| [n]   | [List] of group matches                   | (1)   |
+
+(1)
+:: the [0] element is always value, [1] is group 1 match of any, etc.
+
+[List]: List.md
+
+[Range]: Range.md
+

docs/tutorial.md

@@ -275,6 +275,8 @@ Logical operation could be used the same
 |   ===    |     | Any               | (2)      |
 |   !==    |     | Any               | (2)      |
 |    !=    |     | Any               | (1)      |
+|    =~    |     |                   | (3)      |
+|    !~    |     |                   | (3)      |
 | ++a, a++ |     | Int               |          |
 | --a, a-- |     | Int               |          |
 
@@ -286,6 +288,9 @@ Logical operation could be used the same
 singleton object, like `null`, are referentially equal too, while string different literals even being equal are most
 likely referentially not equal
 
+(3)
+: Implemented now in String and Regex as regular expression match and not match, see [Regex].
+
 Reference quality and object equality example:
 
     assert( null == null)  // singletons
@@ -1285,9 +1290,26 @@ Open-ended ranges could be used to get start and end too:
     assertEquals( "pult", "catapult"[ 4.. ])
     >>> void
 
+
 ### String operations
 
-Concatenation is a `+`: `"hello " + name` works as expected. No confusion.
+Concatenation is a `+`: `"hello " + name` works as expected. No confusion. There is also
+[Regex] support for strings, see the link, for example, whole string match:
+
+    assert( !"123".matches( "\d\d".re ) )
+    assert( "123".matches( "\d\d\d".re ) )
+    >>> void
+
+Extraction:
+
+    "abcd42def"[ "\d+".re ].value
+    >>> "42"
+
+Part match:
+
+    assert( "abc foo def" =~ "f[oO]+".re )
+    assert( "foo" == $~.value )
+    >>> void
 
 Typical set of String functions includes:
 
@@ -1305,17 +1327,24 @@ Typical set of String functions includes:
 | size               | size in characters like `length` because String is [Array] |
 | (args...)          | sprintf-like formatting, see [string formatting]           |
 | [index]            | character at index                                         | 
-| [Range]            | substring at range                                         |
+| [Range]            | substring at range (2)                                     |
+| [Regex]            | find first match of regex, like [Regex.find] (2)           |
 | s1 + s2            | concatenation                                              |
 | s1 += s2           | self-modifying concatenation                               |
 | toReal()           | attempts to parse string as a Real value                   |
 | toInt()            | parse string to Int value                                  |
 | characters()       | create [List] of characters (1)                            |
 | encodeUtf8()       | returns [Buffer] with characters encoded to utf8           |
+| matches(re)        | matches the regular expression (2)                         |
+|                    |                                                            |
+
 
 (1)
 : List is mutable therefore a new copy is created on each call.
 
+(2)
+: See [Regex]
+
 ### Literals
 
 String literal could be multiline:
@@ -1391,3 +1420,5 @@ See [math functions](math.md). Other general purpose functions are:
 [Collection]: Collection.md
 
 [Array]: Array.md
+
+[Regex]: Regex.md

lynglib/build.gradle.kts

@@ -21,7 +21,7 @@ import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl
 import org.jetbrains.kotlin.gradle.dsl.JvmTarget
 
 group = "net.sergeych"
-version = "0.8.15-SNAPSHOT"
+version = "0.9.0-SNAPSHOT"
 
 buildscript {
     repositories {

lynglib/src/commonMain/kotlin/net/sergeych/lyng/Compiler.kt

@@ -1000,6 +1000,7 @@ class Compiler(
             // condition could be a value, in and is clauses:
             // parse several conditions for one then clause
 
+
             // loop cases
             outer@ while (true) {
 
@@ -1466,7 +1467,7 @@ class Compiler(
                 }
             }
         } else {
-            for (i in start ..< end) {
+            for (i in start..<end) {
                 iVar.value = i
                 result = body.execute(forScope)
             }
@@ -2007,6 +2008,8 @@ class Compiler(
             Operator.simple(Token.Type.NEQ, lastPriority) { c, a, b -> ObjBool(a.compareTo(c, b) != 0) },
             Operator.simple(Token.Type.REF_EQ, lastPriority) { _, a, b -> ObjBool(a === b) },
             Operator.simple(Token.Type.REF_NEQ, lastPriority) { _, a, b -> ObjBool(a !== b) },
+            Operator.simple(Token.Type.MATCH, lastPriority) { s, a, b -> a.operatorMatch(s,b) },
+            Operator.simple(Token.Type.NOTMATCH, lastPriority) { s, a, b -> a.operatorNotMatch(s,b) },
             // relational <=,... 5
             Operator.simple(Token.Type.LTE, ++lastPriority) { c, a, b -> ObjBool(a.compareTo(c, b) <= 0) },
             Operator.simple(Token.Type.LT, lastPriority) { c, a, b -> ObjBool(a.compareTo(c, b) < 0) },

lynglib/src/commonMain/kotlin/net/sergeych/lyng/Parser.kt

@@ -20,10 +20,10 @@ package net.sergeych.lyng
 val digitsSet = ('0'..'9').toSet()
 val digits = { d: Char -> d in digitsSet }
 val hexDigits = digitsSet + ('a'..'f') + ('A'..'F')
-val idNextChars = { d: Char -> d.isLetter() || d == '_' || d.isDigit() }
+val idNextChars = { d: Char -> d.isLetter() || d == '_' || d.isDigit() || d == '$' || d == '~' }
 
 @Suppress("unused")
-val idFirstChars = { d: Char -> d.isLetter() || d == '_' }
+val idFirstChars = { d: Char -> d.isLetter() || d == '_' || d == '$' }
 
 fun parseLyng(source: Source): List<Token> {
     val p = Parser(fromPos = source.startPos)
@@ -67,13 +67,16 @@ private class Parser(fromPos: Pos) {
                             pos.advance()
                             Token("===", from, Token.Type.REF_EQ)
                         }
+
                         else -> Token("==", from, Token.Type.EQ)
                     }
-                } else if( currentChar == '>' ) {
+                } else if (currentChar == '>') {
                     pos.advance()
                     Token("=>", from, Token.Type.EQARROW)
-                }
-                else
+                } else if (currentChar == '~') {
+                    pos.advance()
+                    Token("=~", from, Token.Type.MATCH)
+                } else
                     Token("=", from, Token.Type.ASSIGN)
             }
 
@@ -227,6 +230,9 @@ private class Parser(fromPos: Pos) {
                             Token("!==", from, Token.Type.REF_NEQ)
                         } else
                             Token("!=", from, Token.Type.NEQ)
+                    } else if (currentChar == '~') {
+                        pos.advance()
+                        Token("!~", from, Token.Type.NOTMATCH)
                     } else
                         Token("!", from, Token.Type.NOT)
             }
@@ -267,7 +273,7 @@ private class Parser(fromPos: Pos) {
 
             in digitsSet -> {
                 pos.back()
-                decodeNumber(loadChars { it in digitsSet || it == '_'}, from)
+                decodeNumber(loadChars { it in digitsSet || it == '_' }, from)
             }
 
             '\'' -> {
@@ -291,7 +297,7 @@ private class Parser(fromPos: Pos) {
             }
 
             '?' -> {
-                when(currentChar.also { pos.advance() }) {
+                when (currentChar.also { pos.advance() }) {
                     ':' -> Token("??", from, Token.Type.ELVIS)
                     '?' -> Token("??", from, Token.Type.ELVIS)
                     '.' -> Token("?.", from, Token.Type.NULL_COALESCE)
@@ -310,7 +316,7 @@ private class Parser(fromPos: Pos) {
                 // Labels processing is complicated!
                 // some@ statement: label 'some', ID 'statement'
                 // statement@some: ID 'statement', LABEL 'some'!
-                if (ch.isLetter() || ch == '_') {
+                if (idNextChars(ch)) {
                     val text = ch + loadChars(idNextChars)
                     if (currentChar == '@') {
                         pos.advance()
@@ -395,25 +401,24 @@ private class Parser(fromPos: Pos) {
     private fun fixMultilineStringLiteral(source: String): String {
         val sizes = mutableListOf<Int>()
         val lines = source.lines().toMutableList()
-        if( lines.size == 0 ) return ""
-        if( lines[0].isBlank() ) lines.removeFirst()
-        if( lines.isEmpty()) return ""
-        if( lines.last().isBlank() ) lines.removeLast()
+        if (lines.size == 0) return ""
+        if (lines[0].isBlank()) lines.removeFirst()
+        if (lines.isEmpty()) return ""
+        if (lines.last().isBlank()) lines.removeLast()
 
         val normalized = lines.map { l ->
-            if( l.isBlank() ) {
+            if (l.isBlank()) {
                 sizes.add(-1)
                 ""
-            }
-            else {
+            } else {
                 val margin = leftMargin(l)
                 sizes += margin
                 " ".repeat(margin) + l.trim()
             }
         }
         val commonMargin = sizes.filter { it >= 0 }.min()
-        val fixed = if( commonMargin < 1 ) lines else normalized.map {
-            if( it.isBlank() ) "" else it.drop(commonMargin)
+        val fixed = if (commonMargin < 1) lines else normalized.map {
+            if (it.isBlank()) "" else it.drop(commonMargin)
         }
         return fixed.joinToString("\n")
     }
@@ -433,11 +438,26 @@ private class Parser(fromPos: Pos) {
                 '\\' -> {
                     pos.advance() ?: raise("unterminated string")
                     when (currentChar) {
-                        'n' -> {sb.append('\n'); pos.advance()}
-                        'r' -> {sb.append('\r'); pos.advance()}
-                        't' -> {sb.append('\t'); pos.advance()}
-                        '"' -> {sb.append('"'); pos.advance()}
-                        '\\' -> {sb.append('\\'); pos.advance()}
+                        'n' -> {
+                            sb.append('\n'); pos.advance()
+                        }
+
+                        'r' -> {
+                            sb.append('\r'); pos.advance()
+                        }
+
+                        't' -> {
+                            sb.append('\t'); pos.advance()
+                        }
+
+                        '"' -> {
+                            sb.append('"'); pos.advance()
+                        }
+
+                        '\\' -> {
+                            sb.append('\\'); pos.advance()
+                        }
+
                         else -> {
                             sb.append('\\').append(currentChar)
                             pos.advance()
@@ -445,7 +465,7 @@ private class Parser(fromPos: Pos) {
                     }
                 }
 
-                '\n', '\r'-> {
+                '\n', '\r' -> {
                     newlineDetected = true
                     sb.append(currentChar)
                     pos.advance()
@@ -459,7 +479,7 @@ private class Parser(fromPos: Pos) {
         }
         pos.advance()
 
-        val result = sb.toString().let { if( newlineDetected ) fixMultilineStringLiteral(it) else it }
+        val result = sb.toString().let { if (newlineDetected) fixMultilineStringLiteral(it) else it }
 
         return Token(result, start, Token.Type.STRING)
     }
@@ -538,7 +558,7 @@ private class Parser(fromPos: Pos) {
 
     init {
         // skip shebang
-        if( pos.readFragment("#!") )
+        if (pos.readFragment("#!"))
             loadToEndOfLine()
     }
 

lynglib/src/commonMain/kotlin/net/sergeych/lyng/Token.kt

@@ -37,7 +37,7 @@ data class Token(val value: String, val pos: Pos, val type: Type) {
         ASSIGN, PLUSASSIGN, MINUSASSIGN, STARASSIGN, SLASHASSIGN, PERCENTASSIGN,
         PLUS2, MINUS2,
         IN, NOTIN, IS, NOTIS,
-        EQ, NEQ, LT, LTE, GT, GTE, REF_EQ, REF_NEQ,
+        EQ, NEQ, LT, LTE, GT, GTE, REF_EQ, REF_NEQ, MATCH, NOTMATCH,
         SHUTTLE,
         AND, BITAND, OR, BITOR, NOT, BITNOT, DOT, ARROW, EQARROW, QUESTION, COLONCOLON,
         SINLGE_LINE_COMMENT, MULTILINE_COMMENT,

lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/Obj.kt

@@ -178,6 +178,14 @@ open class Obj {
         scope.raiseNotImplemented()
     }
 
+    open suspend fun operatorMatch(scope: Scope, other: Obj): Obj {
+        scope.raiseNotImplemented()
+    }
+
+    open suspend fun operatorNotMatch(scope: Scope, other: Obj): Obj {
+        return operatorMatch(scope,other).logicalNot(scope)
+    }
+
     open suspend fun assign(scope: Scope, other: Obj): Obj? = null
 
     open fun getValue(scope: Scope) = this
@@ -301,6 +309,18 @@ open class Obj {
         return scope
     }
 
+    inline fun <reified R: Obj> cast(scope: Scope): R {
+        castOrNull<R>()?.let { return it }
+        scope.raiseClassCastError("can't cast ${this::class.simpleName} to ${R::class.simpleName}")
+
+    }
+
+    inline fun <reified R: Obj> castOrNull(): R? {
+        (this as? R)?.let { return it }
+        // todo: check for subclasses
+        return null
+    }
+
     companion object {
 
         val rootObjectType = ObjClass("Obj").apply {

lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjRegex.kt

@@ -22,11 +22,20 @@ import net.sergeych.lyng.Scope
 class ObjRegex(val regex: Regex) : Obj() {
     override val objClass = type
 
+    override suspend fun operatorMatch(scope: Scope, other: Obj): Obj {
+        return regex.find(other.cast<ObjString>(scope).value)?.let {
+            scope.addConst("$~", ObjRegexMatch(it))
+            ObjTrue
+        } ?: ObjFalse
+    }
+
+    fun find(s: ObjString): Obj =
+        regex.find(s.value)?.let { ObjRegexMatch(it) } ?: ObjNull
+
     companion object {
         val type by lazy {
             object : ObjClass("Regex") {
                 override suspend fun callOn(scope: Scope): Obj {
-                    println(scope.requireOnlyArg<ObjString>().value)
                     return ObjRegex(
                         scope.requireOnlyArg<ObjString>().value.toRegex()
                     )
@@ -36,8 +45,7 @@ class ObjRegex(val regex: Regex) : Obj() {
                     ObjBool(args.firstAndOnly().toString().matches(thisAs<ObjRegex>().regex))
                 }
                 addFn("find") {
-                    val s = requireOnlyArg<ObjString>().value
-                    thisAs<ObjRegex>().regex.find(s)?.let { ObjRegexMatch(it) } ?: ObjNull
+                    thisAs<ObjRegex>().find(requireOnlyArg<ObjString>())
                 }
                 addFn("findAll") {
                     val s = requireOnlyArg<ObjString>().value
@@ -61,6 +69,7 @@ class ObjRegexMatch(val match: MatchResult) : Obj() {
 
     val objRange: ObjRange by lazy {
         val r = match.range
+
         ObjRange(
             ObjInt(r.first.toLong()),
             ObjInt(r.last.toLong()),
@@ -68,6 +77,19 @@ class ObjRegexMatch(val match: MatchResult) : Obj() {
         )
     }
 
+    override suspend fun toString(scope: Scope,calledFromLyng: Boolean): ObjString {
+        return ObjString("RegexMath(${objRange.toString(scope)},${objGroups.toString(scope)})")
+    }
+
+    override suspend fun getAt(scope: Scope, index: Obj): Obj {
+        return objGroups.getAt(scope, index)
+    }
+
+    override suspend fun compareTo(scope: Scope, other: Obj): Int {
+        if( other === this) return 0
+        return -2
+    }
+
     companion object {
         val type by lazy {
             object : ObjClass("RegexMatch") {

lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjString.kt

@@ -56,16 +56,23 @@ data class ObjString(val value: String) : Obj() {
     }
 
     override suspend fun getAt(scope: Scope, index: Obj): Obj {
-        if (index is ObjInt) return ObjChar(value[index.toInt()])
-        if (index is ObjRange) {
-            val start = if (index.start == null || index.start.isNull) 0 else index.start.toInt()
-            val end = if (index.end == null || index.end.isNull) value.length else {
-                val e = index.end.toInt()
-                if (index.isEndInclusive) e + 1 else e
+        when (index) {
+            is ObjInt -> return ObjChar(value[index.toInt()])
+            is ObjRange -> {
+                val start = if (index.start == null || index.start.isNull) 0 else index.start.toInt()
+                val end = if (index.end == null || index.end.isNull) value.length else {
+                    val e = index.end.toInt()
+                    if (index.isEndInclusive) e + 1 else e
+                }
+                return ObjString(value.substring(start, end))
             }
-            return ObjString(value.substring(start, end))
+
+            is ObjRegex -> {
+                return index.find(this)
+            }
+
+            else -> scope.raiseIllegalArgument("String index must be Int, Regex or Range")
         }
-        scope.raiseIllegalArgument("String index must be Int or Range")
     }
 
     override fun hashCode(): Int {
@@ -96,6 +103,11 @@ data class ObjString(val value: String) : Obj() {
         return value == other.value
     }
 
+    override suspend fun operatorMatch(scope: Scope, other: Obj): Obj {
+        val re = other.cast<ObjRegex>(scope)
+        return re.operatorMatch(scope, this)
+    }
+
     override suspend fun lynonType(): LynonType = LynonType.String
 
     override suspend fun serialize(scope: Scope, encoder: LynonEncoder, lynonType: LynonType?) {
@@ -108,8 +120,9 @@ data class ObjString(val value: String) : Obj() {
                 ObjString(decoder.unpackBinaryData().decodeToString())
         }.apply {
             addFn("toInt") {
-                ObjInt(thisAs<ObjString>().value.toLongOrNull()
-                    ?: raiseIllegalArgument("can't convert to int: $thisObj")
+                ObjInt(
+                    thisAs<ObjString>().value.toLongOrNull()
+                        ?: raiseIllegalArgument("can't convert to int: $thisObj")
                 )
             }
             addFn("startsWith") {
@@ -160,6 +173,22 @@ data class ObjString(val value: String) : Obj() {
             addFn("trim") {
                 thisAs<ObjString>().value.trim().let(::ObjString)
             }
+            addFn("matches") {
+                val s = requireOnlyArg<Obj>()
+                val self = thisAs<ObjString>().value
+                ObjBool(
+                    when (s) {
+                        is ObjRegex -> self.matches(s.regex)
+                        is ObjString -> {
+                            if (s.value == ".*") true
+                            else self.matches(s.value.toRegex())
+                        }
+
+                        else ->
+                            raiseIllegalArgument("can't match ${s.objClass.className}: required Regex or String")
+                    }
+                )
+            }
         }
     }
 }

lynglib/src/commonTest/kotlin/ScriptTest.kt

@@ -2242,6 +2242,45 @@ class ScriptTest {
         )
     }
 
+    @Test
+    fun testParseSpecialVars() {
+        val l = parseLyng("$~".toSource("test$~"))
+        println(l)
+        assertEquals(Token.Type.ID, l[0].type)
+        assertEquals("$~", l[0].value)
+    }
+
+    @Test
+    fun testMatchOperator() = runTest {
+        eval("""
+            assert( "abc123".matches(".*\d{3}") )
+            assert( ".*\d{3}".re =~ "abc123" )
+            assert( "abc123" =~ ".*\d{3}".re )
+            assert( "abc123" !~ ".*\d{4}".re )
+            
+            "abc123" =~ ".*(\d)(\d)(\d)$".re
+            println($~)
+            assertEquals("1", $~[1])
+            assertEquals("2", $~[2])
+            assertEquals("3", $~[3])
+            assertEquals("abc123", $~[0])
+        """.trimIndent())
+    }
+
+//    @Test
+//    fun testWhenMatch() = runTest {
+//        eval(
+//            """
+//            when("abc123") {
+//                ".*(\d)(\d)(\d)".re -> { x ->
+//                    assertEquals("123", x[0])
+//                }
+//                else -> assert(false)
+//            }
+//            """.trimIndent()
+//        )
+//    }
+
     @Test
     fun testWhenSample1() = runTest {
         eval(
@@ -3247,7 +3286,7 @@ class ScriptTest {
     }
 
 
-//    @Test
+    //    @Test
     fun testMinimumOptimization() = runTest {
         val x = Scope().eval(
             """

lynglib/src/jvmTest/kotlin/BookTest.kt

@@ -332,4 +332,8 @@ class BookTest {
         runDocTests("../docs/Array.md")
     }
 
+    @Test
+    fun testRegex() = runBlocking {
+        runDocTests("../docs/Regex.md")
+    }
 }