Merge pull request #371 from russellbanks/add-plain-except-ambiguous

Add SingleLineStringStyle.PlainExceptAmbiguous and AmbiguousEscapeStyle
charleskorn · Jan 28, 2023 · f4e94d1 · f4e94d1
2 parents f40ac61 + d80f1e0
commit f4e94d1
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diff --git a/src/commonMain/kotlin/com/charleskorn/kaml/YamlConfiguration.kt b/src/commonMain/kotlin/com/charleskorn/kaml/YamlConfiguration.kt
@@ -31,6 +31,7 @@ package com.charleskorn.kaml
  * * [encodingIndentationSize]: number of spaces to use as indentation when encoding objects as YAML
  * * [breakScalarsAt]: maximum length of scalars when encoding objects as YAML (scalars exceeding this length will be split into multiple lines)
  * * [sequenceStyle]: how sequences (aka lists and arrays) should be formatted. See [SequenceStyle] for an example of each
+ * * [ambiguousQuoteStyle]: how strings should be escaped when [singleLineStringStyle] is [SingleLineStringStyle.PlainExceptAmbiguous] and the value is ambiguous
  * * [sequenceBlockIndent]: number of spaces to use as indentation for sequences, if [sequenceStyle] set to [SequenceStyle.Block]
  */
 public data class YamlConfiguration constructor(
@@ -44,6 +45,7 @@ public data class YamlConfiguration constructor(
     internal val sequenceStyle: SequenceStyle = SequenceStyle.Block,
     internal val singleLineStringStyle: SingleLineStringStyle = SingleLineStringStyle.DoubleQuoted,
     internal val multiLineStringStyle: MultiLineStringStyle = singleLineStringStyle.multiLineStringStyle,
+    internal val ambiguousQuoteStyle: AmbiguousQuoteStyle = AmbiguousQuoteStyle.DoubleQuoted,
     internal val sequenceBlockIndent: Int = 0,
 )
 
@@ -83,12 +85,27 @@ public enum class SingleLineStringStyle {
     DoubleQuoted,
     SingleQuoted,
     Plain,
+
+    /**
+     * This is the same as [SingleLineStringStyle.Plain], except strings that could be misinterpreted as other types
+     * will be quoted with the escape style defined in [AmbiguousQuoteStyle].
+     *
+     * For example, the strings "True", "0xAB", "1" and "1.2" would all be quoted,
+     * while "1.2.3" and "abc" would not be quoted.
+     */
+    PlainExceptAmbiguous,
     ;
 
     public val multiLineStringStyle: MultiLineStringStyle
         get() = when (this) {
             DoubleQuoted -> MultiLineStringStyle.DoubleQuoted
             SingleQuoted -> MultiLineStringStyle.SingleQuoted
             Plain -> MultiLineStringStyle.Plain
+            PlainExceptAmbiguous -> MultiLineStringStyle.Plain
         }
 }
+
+public enum class AmbiguousQuoteStyle {
+    DoubleQuoted,
+    SingleQuoted,
+}
diff --git a/src/commonTest/kotlin/com/charleskorn/kaml/YamlWritingTest.kt b/src/commonTest/kotlin/com/charleskorn/kaml/YamlWritingTest.kt
@@ -200,6 +200,101 @@ class YamlWritingTest : DescribeSpec({
                         """.trimMargin()
                 }
             }
+
+            context("serializing a string with the value of an integer using SingleLineStringStyle.PlainExceptAmbiguous") {
+                val output = Yaml(configuration = YamlConfiguration(singleLineStringStyle = SingleLineStringStyle.PlainExceptAmbiguous)).encodeToString(String.serializer(), "12")
+
+                it("returns the value serialized in the expected YAML form, escaping the integer") {
+                    output shouldBe """"12""""
+                }
+            }
+
+            context("serializing a string with the value of a boolean using SingleLineStringStyle.PlainExceptAmbiguous") {
+                val output = Yaml(configuration = YamlConfiguration(singleLineStringStyle = SingleLineStringStyle.PlainExceptAmbiguous)).encodeToString(String.serializer(), "true")
+
+                it("returns the value serialized in the expected YAML form, escaping the boolean") {
+                    output shouldBe """"true""""
+                }
+            }
+
+            context("serializing a string with the value of an float using SingleLineStringStyle.PlainExceptAmbiguous") {
+                val output = Yaml(configuration = YamlConfiguration(singleLineStringStyle = SingleLineStringStyle.PlainExceptAmbiguous)).encodeToString(String.serializer(), "1.2")
+
+                it("returns the value serialized in the expected YAML form, escaping the float") {
+                    output shouldBe """"1.2""""
+                }
+            }
+
+            context("serializing an unambiguous numerical string using SingleLineStringStyle.PlainExceptAmbiguous") {
+                val output = Yaml(configuration = YamlConfiguration(singleLineStringStyle = SingleLineStringStyle.PlainExceptAmbiguous)).encodeToString(String.serializer(), "1.2.3")
+
+                it("returns the value serialized in the expected YAML form, without being escaped") {
+                    output shouldBe "1.2.3"
+                }
+            }
+
+            context("serializing an int using SingleLineStringStyle.PlainExceptAmbiguous") {
+                val output = Yaml(configuration = YamlConfiguration(singleLineStringStyle = SingleLineStringStyle.PlainExceptAmbiguous)).encodeToString(Int.serializer(), 123)
+
+                it("returns the value serialized in the expected YAML form, without being escaped") {
+                    output shouldBe "123"
+                }
+            }
+
+            context("serializing a float using SingleLineStringStyle.PlainExceptAmbiguous") {
+                val output = Yaml(configuration = YamlConfiguration(singleLineStringStyle = SingleLineStringStyle.PlainExceptAmbiguous)).encodeToString(Float.serializer(), 1.2f)
+
+                it("returns the value serialized in the expected YAML form, without being escaped") {
+                    output shouldBe "1.2"
+                }
+            }
+
+            context("serializing a boolean using SingleLineStringStyle.PlainExceptAmbiguous") {
+                val output = Yaml(configuration = YamlConfiguration(singleLineStringStyle = SingleLineStringStyle.PlainExceptAmbiguous)).encodeToString(Boolean.serializer(), true)
+
+                it("returns the value serialized in the expected YAML form, without being escaped") {
+                    output shouldBe "true"
+                }
+            }
+
+            context("serializing a string with the value of an integer using SingleLineStringStyle.PlainExceptAmbiguous, escaping with single-quotes") {
+                val output = Yaml(
+                    configuration = YamlConfiguration(
+                        singleLineStringStyle = SingleLineStringStyle.PlainExceptAmbiguous,
+                        ambiguousQuoteStyle = AmbiguousQuoteStyle.SingleQuoted,
+                    ),
+                ).encodeToString(String.serializer(), "12")
+
+                it("returns the value serialized in the expected YAML form, escaping the integer with single-quotes") {
+                    output shouldBe """'12'"""
+                }
+            }
+
+            context("serializing a string with the value of a boolean using SingleLineStringStyle.PlainExceptAmbiguous, escaping with single-quotes") {
+                val output = Yaml(
+                    configuration = YamlConfiguration(
+                        singleLineStringStyle = SingleLineStringStyle.PlainExceptAmbiguous,
+                        ambiguousQuoteStyle = AmbiguousQuoteStyle.SingleQuoted,
+                    ),
+                ).encodeToString(String.serializer(), "true")
+
+                it("returns the value serialized in the expected YAML form, escaping the boolean with single-quotes") {
+                    output shouldBe """'true'"""
+                }
+            }
+
+            context("serializing a string with the value of an float using SingleLineStringStyle.PlainExceptAmbiguous, escaping with single-quotes") {
+                val output = Yaml(
+                    configuration = YamlConfiguration(
+                        singleLineStringStyle = SingleLineStringStyle.PlainExceptAmbiguous,
+                        ambiguousQuoteStyle = AmbiguousQuoteStyle.SingleQuoted,
+                    ),
+                ).encodeToString(String.serializer(), "1.2")
+
+                it("returns the value serialized in the expected YAML form, escaping the float with single-quotes") {
+                    output shouldBe """'1.2'"""
+                }
+            }
         }
 
         describe("serializing enumeration values") {

diff --git a/src/jvmMain/kotlin/com/charleskorn/kaml/YamlOutput.kt b/src/jvmMain/kotlin/com/charleskorn/kaml/YamlOutput.kt
@@ -88,6 +88,7 @@ internal class YamlOutput(
         } else {
             when {
                 value.contains('\n') -> emitQuotedScalar(value, configuration.multiLineStringStyle.scalarStyle)
+                configuration.singleLineStringStyle == SingleLineStringStyle.PlainExceptAmbiguous && value.isAmbiguous() -> emitQuotedScalar(value, configuration.ambiguousQuoteStyle.scalarStyle)
                 else -> emitQuotedScalar(value, configuration.singleLineStringStyle.scalarStyle)
             }
         }
@@ -180,6 +181,21 @@ internal class YamlOutput(
         return typeName
     }
 
+    private fun String.isAmbiguous(): Boolean {
+        return when {
+            isEmpty() -> true
+            toBigIntegerOrNull() != null -> true
+            startsWith("0x") -> true
+            startsWith("0o") -> true
+            toDoubleOrNull() != null -> true
+            startsWith("#") -> true
+            else -> this in listOf(
+                "~", "-", ".inf", ".Inf", ".INF", "-.inf", "-.Inf", "-.INF", ".nan", ".NaN", ".NAN", "-.nan", "-.NaN",
+                "-.NAN", "null", "Null", "NULL", "true", "True", "TRUE", "false", "False", "FALSE",
+            )
+        }
+    }
+
     private val SequenceStyle.flowStyle: FlowStyle
         get() = when (this) {
             SequenceStyle.Block -> FlowStyle.BLOCK
@@ -199,6 +215,13 @@ internal class YamlOutput(
             SingleLineStringStyle.DoubleQuoted -> ScalarStyle.DOUBLE_QUOTED
             SingleLineStringStyle.SingleQuoted -> ScalarStyle.SINGLE_QUOTED
             SingleLineStringStyle.Plain -> ScalarStyle.PLAIN
+            SingleLineStringStyle.PlainExceptAmbiguous -> ScalarStyle.PLAIN
+        }
+
+    private val AmbiguousQuoteStyle.scalarStyle: ScalarStyle
+        get() = when (this) {
+            AmbiguousQuoteStyle.DoubleQuoted -> ScalarStyle.DOUBLE_QUOTED
+            AmbiguousQuoteStyle.SingleQuoted -> ScalarStyle.SINGLE_QUOTED
         }
 
     companion object {