Fix part of #209: Introduce a tokenizer and parser for NumberWithUnits

model/src/main/proto/interaction_object.proto

@@ -53,6 +53,162 @@ message NumberUnit {
   int32 exponent = 2;
 }
 
+// Represents a number with explicitly-defined units.
+message NumberWithUnitsExpression {
+  // The different types of numeric values that can have units.
+  oneof number_type {
+    // Indicates the value is a real number (decimal or integer).
+    double real = 1;
+
+    // Indicates the value is a fraction.
+    Fraction fraction = 2;
+  }
+
+  // Explicitly captures where units appear relative to the numeric value.
+  // This ensures parser output preserves format-specific semantics.
+  oneof expression_format {
+    // Units precede the value.
+    PrefixValueExpression prefix_value_expression = 3;
+
+    // Units follow the value.
+    ValueSuffixExpression value_suffix_expression = 4;
+
+    // Units appear on both sides of the value.
+    PrefixValueSuffixExpression prefix_value_suffix_expression = 5;
+  }
+}
+
+// Represents expressions where units appear before the number.
+message PrefixValueExpression {
+  repeated NumberUnitExpression prefix_units = 1;
+}
+
+// Represents expressions where units appear after the number.
+message ValueSuffixExpression {
+  repeated NumberUnitExpression suffix_units = 1;
+}
+
+// Represents expressions where units appear both before and after the number.
+message PrefixValueSuffixExpression {
+  repeated NumberUnitExpression prefix_units = 1;
+  repeated NumberUnitExpression suffix_units = 2;
+}
+
+// Represents a specific unit with an exponent.
+message NumberUnitExpression {
+  // Supported SI prefixes.
+  // These are combined with [unit].
+  enum SiPrefix {
+    SI_PREFIX_UNSPECIFIED = 0;
+    DECA = 1;
+    HECTO = 2;
+    KILO = 3;
+    MEGA = 4;
+    GIGA = 5;
+    TERA = 6;
+    PETA = 7;
+    EXA = 8;
+    ZETTA = 9;
+    YOTTA = 10;
+    DECI = 11;
+    CENTI = 12;
+    MILLI = 13;
+    MICRO = 14;
+    NANO = 15;
+    PICO = 16;
+    FEMTO = 17;
+    ATTO = 18;
+    ZEPTO = 19;
+    YOCTO = 20;
+  }
+
+  // The supported base unit types. Prefixed combinations are intentionally not enumerated here.
+  enum Unit {
+    UNIT_UNSPECIFIED = 0;
+
+    // Length units
+    METER = 1;
+    INCH = 2;
+    FOOT = 3;
+    YARD = 4;
+
+    // Mass units
+    GRAM = 5;
+    GRAIN = 6;
+    OUNCE = 7;
+
+    // Area units
+    SQUARE_METER = 8;
+    SQUARE_INCH = 9;
+    SQUARE_FOOT = 10;
+    SQUARE_YARD = 11;
+
+    // Volume unit
+    CUBIC_METER = 12;
+    LITER = 13;
+    CUBIC_CENTIMETER = 14;
+    CUBIC_INCH = 15;
+    CUBIC_FOOT = 16;
+    CUBIC_YARD = 17;
+
+    // Temperature units
+    KELVIN = 18;
+    CELSIUS = 19;
+
+    // Angle units
+    RADIAN = 20;
+    DEGREE = 21;
+
+    // Time units
+    SECOND = 22;
+    MINUTE = 23;
+    HOUR = 24;
+
+    // Frequency units
+    HERTZ = 25;
+
+    // Amount of substance
+    MOLE = 26;
+
+    // Luminous intensity
+    CANDELA = 27;
+
+    // Force
+    NEWTON = 28;
+
+    // Energy
+    JOULE = 29;
+
+    // Power
+    WATT = 30;
+
+    // Pressure
+    PASCAL = 31;
+
+    // Electricity
+    AMPERE = 32;
+    VOLT = 33;
+    OHM = 34;
+
+    // Currency units
+    DOLLAR = 35;
+    CENT = 36;
+    RUPEE = 37;
+    PAISA = 38;
+  }
+
+  // The specific unit value.
+  Unit unit = 1;
+
+  // The exponent (power) of this unit in the expression.
+  // Positive values indicate numerator units, negative values indicate denominator units.
+  int32 exponent = 2;
+
+  // Optional SI prefix used with [unit].
+  // Leave as SI_PREFIX_UNSPECIFIED for units that do not have a prefix.
+  SiPrefix si_prefix = 3;
+}
+
 // Structure for a ListOfString object.
 message ListOfSetsOfHtmlStrings {
   repeated StringList set_of_html_strings = 1;

scripts/assets/file_content_validation_checks.textproto

@@ -335,6 +335,7 @@ file_content_checks {
   exempted_file_name: "utility/src/test/java/org/oppia/android/util/math/MathExpressionExtensionsTest.kt"
   exempted_file_name: "utility/src/test/java/org/oppia/android/util/math/MathExpressionParserTest.kt"
   exempted_file_name: "utility/src/test/java/org/oppia/android/util/math/MathTokenizerTest.kt"
+  exempted_file_name: "utility/src/test/java/org/oppia/android/util/math/NumberWithUnitsTokenizerTest.kt"
   exempted_file_name: "utility/src/test/java/org/oppia/android/util/math/PolynomialExtensionsTest.kt"
   exempted_file_name: "utility/src/test/java/org/oppia/android/util/math/RealExtensionsTest.kt"
   exempted_file_name: "utility/src/test/java/org/oppia/android/util/profile/ProfileNameValidatorTest.kt"

scripts/assets/test_file_exemptions.textproto

@@ -4351,6 +4351,14 @@ test_file_exemption {
   exempted_file_path: "testing/src/main/java/org/oppia/android/testing/logging/SyncStatusTestModule.kt"
   override_min_coverage_percent_required: 0
 }
+test_file_exemption {
+  exempted_file_path: "testing/src/main/java/org/oppia/android/testing/math/NumberWithUnitsSubject.kt"
+  test_file_not_required: true
+}
+test_file_exemption {
+  exempted_file_path: "testing/src/main/java/org/oppia/android/testing/math/NumberWithUnitsTokenSubject.kt"
+  test_file_not_required: true
+}
 test_file_exemption {
   exempted_file_path: "testing/src/main/java/org/oppia/android/testing/mockito/MockitoKotlinHelper.kt"
   test_file_not_required: true
@@ -4647,6 +4655,10 @@ test_file_exemption {
   exempted_file_path: "utility/src/main/java/org/oppia/android/util/math/MathParsingError.kt"
   test_file_not_required: true
 }
+test_file_exemption {
+  exempted_file_path: "utility/src/main/java/org/oppia/android/util/math/NumberWithUnitsParsingError.kt"
+  test_file_not_required: true
+}
 test_file_exemption {
   exempted_file_path: "utility/src/main/java/org/oppia/android/util/networking/ConnectionStatus.kt"
   test_file_not_required: true

testing/src/main/java/org/oppia/android/testing/math/BUILD.bazel

@@ -140,3 +140,35 @@ kt_android_library(
         "//utility/src/main/java/org/oppia/android/util/math:tokenizer",
     ],
 )
+
+kt_android_library(
+    name = "number_with_units_subject",
+    testonly = True,
+    srcs = [
+        "NumberWithUnitsSubject.kt",
+    ],
+    visibility = [
+        "//:oppia_testing_visibility",
+    ],
+    deps = [
+        ":fraction_subject",
+        "//model/src/main/proto:interaction_object_java_proto_lite",
+        "//third_party:com_google_truth_extensions_truth-liteproto-extension",
+        "//third_party:com_google_truth_truth",
+    ],
+)
+
+kt_android_library(
+    name = "number_with_units_token_subject",
+    testonly = True,
+    srcs = [
+        "NumberWithUnitsTokenSubject.kt",
+    ],
+    visibility = [
+        "//:oppia_testing_visibility",
+    ],
+    deps = [
+        "//third_party:com_google_truth_truth",
+        "//utility/src/main/java/org/oppia/android/util/math:number_with_units_tokenizer",
+    ],
+)