Swift: QLDoc BuiltinLiteralExpr subclasses and add BuiltinLiteral.getValueString.

Author: geoffw0

swift/ql/lib/codeql/swift/elements/expr/BooleanLiteralExpr.qll

@@ -1,5 +1,13 @@
 private import codeql.swift.generated.expr.BooleanLiteralExpr
 
+/**
+ * An integer literal. For example `true` in:
+ * ```
+ * let x = true
+ * ```
+ */
 class BooleanLiteralExpr extends Generated::BooleanLiteralExpr {
   override string toString() { result = this.getValue().toString() }
+
+  override string getValueString() { result = this.getValue().toString() }
 }

swift/ql/lib/codeql/swift/elements/expr/BuiltinLiteralExpr.qll

@@ -1,5 +1,13 @@
 private import codeql.swift.generated.expr.IntegerLiteralExpr
 
+/**
+ * An integer literal. For example `1` in:
+ * ```
+ * let x = 1
+ * ```
+ */
 class IntegerLiteralExpr extends Generated::IntegerLiteralExpr {
   override string toString() { result = this.getStringValue() }
+
+  override string getValueString() { result = this.getStringValue() }
 }

swift/ql/lib/codeql/swift/elements/expr/IntegerLiteralExpr.qll

@@ -1,5 +1,13 @@
 private import codeql.swift.generated.expr.MagicIdentifierLiteralExpr
 
+/**
+ * An identifier literal that is expanded at compile time. For example `#file` in:
+ * ```
+ * let x = #file
+ * ```
+ */
 class MagicIdentifierLiteralExpr extends Generated::MagicIdentifierLiteralExpr {
   override string toString() { result = "#..." }
+
+  override string getValueString() { none() } // TODO: value not yet extracted
 }

swift/ql/lib/codeql/swift/elements/expr/LiteralExpr.qll

@@ -1,5 +1,13 @@
 private import codeql.swift.generated.expr.StringLiteralExpr
 
+/**
+ * A string literal. For example `"abc"` in:
+ * ```
+ * let x = "abc"
+ * ```
+ */
 class StringLiteralExpr extends Generated::StringLiteralExpr {
   override string toString() { result = this.getValue() }
+
+  override string getValueString() { result = this.getValue() }
 }