Add abs, round, floor, ceil operators (#11653)

* Add abs, round, floor, ceil operators

Port of https://github.com/mapbox/mapbox-gl-js/pull/6496

* [ios, macos] Simplified abs, ceiling, floor expressions

* [ios, macos] Added rounding expression function

* [android] - binding integration for round, ceil, floor and abs expressions

* Update mapbox-gl-js to include non-integer rounding test

* Drop extra braces

* mapbox-gl-js -> master

* Update style-spec docs -> PropertyFactory.java

11 files changed, 316 insertions, 32 deletions

diff --git a/mapbox-gl-js b/mapbox-gl-js
-Subproject b01859294fec88111601028a539e45be1f08866
+Subproject 6b96d69ab54b149db1f6ef06daed37379ac0744
diff --git a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/expressions/Expression.java b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/expressions/Expression.java
index 05c67018a4..fa4a802e13 100644
--- a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/expressions/Expression.java
+++ b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/expressions/Expression.java
@@ -81,7 +81,6 @@ import java.util.List;
  * )
  * }
  * </pre>
- *
  */
 public class Expression {
 
@@ -1061,6 +1060,7 @@ public class Expression {
    * );
    * }
    * </pre>
+   *
    * @return expression
    * @see <a href="https://www.mapbox.com/mapbox-gl-js/style-spec/#expressions-properties">Style specification</a>
    */
@@ -1081,6 +1081,7 @@ public class Expression {
    * );
    * }
    * </pre>
+   *
    * @return expression
    * @see <a href="https://www.mapbox.com/mapbox-gl-js/style-spec/#expressions-geometry-types">Style specification</a>
    */
@@ -2295,6 +2296,185 @@ public class Expression {
   }
 
   /**
+   * Rounds the input to the nearest integer.
+   * Halfway values are rounded away from zero.
+   * For example `[\"round\", -1.5]` evaluates to -2.
+   * <p>
+   * Example usage:
+   * </p>
+   * <pre>
+   * {@code
+   * CircleLayer circleLayer = new CircleLayer("layer-id", "source-id");
+   * circleLayer.setProperties(
+   *     circleRadius(round(pi()))
+   * );
+   * }
+   * </pre>
+   *
+   * @param expression number expression to round
+   * @return expression
+   * @see <a href="https://www.mapbox.com/mapbox-gl-js/style-spec/#expressions-round">Style specification</a>
+   */
+  public static Expression round(Expression expression) {
+    return new Expression("round", expression);
+  }
+
+  /**
+   * Rounds the input to the nearest integer.
+   * Halfway values are rounded away from zero.
+   * For example `[\"round\", -1.5]` evaluates to -2.
+   * <p>
+   * Example usage:
+   * </p>
+   * <pre>
+   * {@code
+   * CircleLayer circleLayer = new CircleLayer("layer-id", "source-id");
+   * circleLayer.setProperties(
+   *     circleRadius(round(3.14159265359f))
+   * );
+   * }
+   * </pre>
+   *
+   * @param number number to round
+   * @return expression
+   * @see <a href="https://www.mapbox.com/mapbox-gl-js/style-spec/#expressions-round">Style specification</a>
+   */
+  public static Expression round(Number number) {
+    return round(literal(number));
+  }
+
+  /**
+   * Returns the absolute value of the input.
+   * <p>
+   * Example usage:
+   * </p>
+   * <pre>
+   * {@code
+   * CircleLayer circleLayer = new CircleLayer("layer-id", "source-id");
+   * circleLayer.setProperties(
+   *     circleRadius(abs(subtract(pi())))
+   * );
+   * }
+   * </pre>
+   *
+   * @param expression number expression to get absolute value from
+   * @return expression
+   * @see <a href="https://www.mapbox.com/mapbox-gl-js/style-spec/#expressions-abs">Style specification</a>
+   */
+  public static Expression abs(Expression expression) {
+    return new Expression("abs", expression);
+  }
+
+  /**
+   * Returns the absolute value of the input.
+   * <p>
+   * Example usage:
+   * </p>
+   * <pre>
+   * {@code
+   * CircleLayer circleLayer = new CircleLayer("layer-id", "source-id");
+   * circleLayer.setProperties(
+   *     circleRadius(abs(-3.14159265359f))
+   * );
+   * }
+   * </pre>
+   *
+   * @param number number to get absolute value from
+   * @return expression
+   * @see <a href="https://www.mapbox.com/mapbox-gl-js/style-spec/#expressions-abs">Style specification</a>
+   */
+  public static Expression abs(Number number) {
+    return abs(literal(number));
+  }
+
+  /**
+   * Returns the smallest integer that is greater than or equal to the input.
+   * <p>
+   * Example usage:
+   * </p>
+   * <pre>
+   * {@code
+   * CircleLayer circleLayer = new CircleLayer("layer-id", "source-id");
+   * circleLayer.setProperties(
+   *     circleRadius(ceil(pi()))
+   * );
+   * }
+   * </pre>
+   *
+   * @param expression number expression to get value from
+   * @return expression
+   * @see <a href="https://www.mapbox.com/mapbox-gl-js/style-spec/#expressions-abs">Style specification</a>
+   */
+  public static Expression ceil(Expression expression) {
+    return new Expression("ceil", expression);
+  }
+
+  /**
+   * Returns the smallest integer that is greater than or equal to the input.
+   * <p>
+   * Example usage:
+   * </p>
+   * <pre>
+   * {@code
+   * CircleLayer circleLayer = new CircleLayer("layer-id", "source-id");
+   * circleLayer.setProperties(
+   *     circleRadius(ceil(3.14159265359))
+   * );
+   * }
+   * </pre>
+   * @param number number to get value from
+   * @return expression
+   * @see <a href="https://www.mapbox.com/mapbox-gl-js/style-spec/#expressions-abs">Style specification</a>
+   */
+  public static Expression ceil(Number number) {
+    return ceil(literal(number));
+  }
+
+  /**
+   * Returns the largest integer that is less than or equal to the input.
+   * <p>
+   * Example usage:
+   * </p>
+   * <pre>
+   * {@code
+   * CircleLayer circleLayer = new CircleLayer("layer-id", "source-id");
+   * circleLayer.setProperties(
+   *     circleRadius(floor(pi()))
+   * );
+   * }
+   * </pre>
+   *
+   * @param expression number expression to get value from
+   * @return expression
+   * @see <a href="https://www.mapbox.com/mapbox-gl-js/style-spec/#expressions-abs">Style specification</a>
+   */
+  public static Expression floor(Expression expression) {
+    return new Expression("floor", expression);
+  }
+
+  /**
+   * Returns the largest integer that is less than or equal to the input.
+   * <p>
+   * Example usage:
+   * </p>
+   * <pre>
+   * {@code
+   * CircleLayer circleLayer = new CircleLayer("layer-id", "source-id");
+   * circleLayer.setProperties(
+   *     circleRadius(floor(pi()))
+   * );
+   * }
+   * </pre>
+   *
+   * @param number number to get value from
+   * @return expression
+   * @see <a href="https://www.mapbox.com/mapbox-gl-js/style-spec/#expressions-abs">Style specification</a>
+   */
+  public static Expression floor(Number number) {
+    return floor(literal(number));
+  }
+
+  /**
    * Returns the input string converted to uppercase.
    * <p>
    * Follows the Unicode Default Case Conversion algorithm
@@ -3128,6 +3308,7 @@ public class Expression {
    * );
    * }
    * </pre>
+   *
    * @param expression base number expression
    * @return expression
    * @see <a href="https://www.mapbox.com/mapbox-gl-js/style-spec/#expressions-interpolate">Style specification</a>
diff --git a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/layers/PropertyFactory.java b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/layers/PropertyFactory.java
index 66d78a40e5..4289deeda3 100644
--- a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/layers/PropertyFactory.java
+++ b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/layers/PropertyFactory.java
@@ -1856,7 +1856,7 @@ public class PropertyFactory {
   }
 
   /**
-   * Name of image in sprite to use for drawing an image background. Within literal values and zoom functions, property names enclosed in curly brackets (e.g. `{token}`) are replaced with the value of the named property. Expressions and property functions do not support this syntax; for equivalent functionality in expressions, use the [`concat`](#expressions-concat) and [`get`](#expressions-get) operators.
+   * Name of image in sprite to use for drawing an image background.
    *
    * @param value a String value
    * @return property wrapper around String
@@ -1866,7 +1866,7 @@ public class PropertyFactory {
   }
 
   /**
-   * Name of image in sprite to use for drawing an image background. Within literal values and zoom functions, property names enclosed in curly brackets (e.g. `{token}`) are replaced with the value of the named property. Expressions and property functions do not support this syntax; for equivalent functionality in expressions, use the [`concat`](#expressions-concat) and [`get`](#expressions-get) operators.
+   * Name of image in sprite to use for drawing an image background.
    *
    * @param value a String value
    * @return property wrapper around String
@@ -2036,7 +2036,7 @@ public class PropertyFactory {
   }
 
   /**
-   * Value to use for a text label. Within literal values and zoom functions, property names enclosed in curly brackets (e.g. `{token}`) are replaced with the value of the named property. Expressions and property functions do not support this syntax; for equivalent functionality in expressions, use the [`concat`](#expressions-concat) and [`get`](#expressions-get) operators.
+   * Value to use for a text label.
    *
    * @param value a String value
    * @return property wrapper around String
@@ -2046,7 +2046,7 @@ public class PropertyFactory {
   }
 
   /**
-   * Value to use for a text label. Within literal values and zoom functions, property names enclosed in curly brackets (e.g. `{token}`) are replaced with the value of the named property. Expressions and property functions do not support this syntax; for equivalent functionality in expressions, use the [`concat`](#expressions-concat) and [`get`](#expressions-get) operators.
+   * Value to use for a text label.
    *
    * @param value a String value
    * @return property wrapper around String
diff --git a/platform/android/MapboxGLAndroidSDK/src/test/java/com/mapbox/mapboxsdk/style/expressions/ExpressionTest.java b/platform/android/MapboxGLAndroidSDK/src/test/java/com/mapbox/mapboxsdk/style/expressions/ExpressionTest.java
index 5694242a0a..45833e8556 100644
--- a/platform/android/MapboxGLAndroidSDK/src/test/java/com/mapbox/mapboxsdk/style/expressions/ExpressionTest.java
+++ b/platform/android/MapboxGLAndroidSDK/src/test/java/com/mapbox/mapboxsdk/style/expressions/ExpressionTest.java
@@ -6,6 +6,7 @@ import org.junit.Test;
 
 import java.util.Arrays;
 
+import static com.mapbox.mapboxsdk.style.expressions.Expression.abs;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.acos;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.all;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.any;
@@ -14,6 +15,7 @@ import static com.mapbox.mapboxsdk.style.expressions.Expression.asin;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.at;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.atan;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.bool;
+import static com.mapbox.mapboxsdk.style.expressions.Expression.ceil;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.coalesce;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.color;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.concat;
@@ -24,6 +26,7 @@ import static com.mapbox.mapboxsdk.style.expressions.Expression.downcase;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.e;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.eq;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.exponential;
+import static com.mapbox.mapboxsdk.style.expressions.Expression.floor;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.geometryType;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.get;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.gt;
@@ -56,6 +59,7 @@ import static com.mapbox.mapboxsdk.style.expressions.Expression.product;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.properties;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.rgb;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.rgba;
+import static com.mapbox.mapboxsdk.style.expressions.Expression.round;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.sin;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.sqrt;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.step;
@@ -1105,4 +1109,60 @@ public class ExpressionTest {
     );
     expression.toArray();
   }
+
+  @Test
+  public void testRound() {
+    Object[] expected = new Object[] {"round", 2.2f};
+    Object[] actual = round(2.2f).toArray();
+    assertTrue("expression should match", Arrays.deepEquals(expected, actual));
+  }
+
+  @Test
+  public void testRoundLiteral() {
+    Object[] expected = new Object[] {"round", 2.2f};
+    Object[] actual = round(literal(2.2f)).toArray();
+    assertTrue("expression should match", Arrays.deepEquals(expected, actual));
+  }
+
+  @Test
+  public void testAbs() {
+    Object[] expected = new Object[] {"abs", -2.2f};
+    Object[] actual = abs(-2.2f).toArray();
+    assertTrue("expression should match", Arrays.deepEquals(expected, actual));
+  }
+
+  @Test
+  public void testAbsLiteral() {
+    Object[] expected = new Object[] {"abs", -2.2f};
+    Object[] actual = abs(literal(-2.2f)).toArray();
+    assertTrue("expression should match", Arrays.deepEquals(expected, actual));
+  }
+
+  @Test
+  public void testCeil() {
+    Object[] expected = new Object[] {"ceil", 2.2f};
+    Object[] actual = ceil(2.2f).toArray();
+    assertTrue("expression should match", Arrays.deepEquals(expected, actual));
+  }
+
+  @Test
+  public void testCeilLiteral() {
+    Object[] expected = new Object[] {"ceil", 2.2f};
+    Object[] actual = ceil(literal(2.2f)).toArray();
+    assertTrue("expression should match", Arrays.deepEquals(expected, actual));
+  }
+
+  @Test
+  public void testFloor() {
+    Object[] expected = new Object[] {"floor", 2.2f};
+    Object[] actual = floor(2.2f).toArray();
+    assertTrue("expression should match", Arrays.deepEquals(expected, actual));
+  }
+
+  @Test
+  public void testFloorLiteral() {
+    Object[] expected = new Object[] {"floor", 2.2f};
+    Object[] actual = floor(literal(2.2f)).toArray();
+    assertTrue("expression should match", Arrays.deepEquals(expected, actual));
+  }
 }
\ No newline at end of file
diff --git a/platform/darwin/docs/guides/For Style Authors.md.ejs b/platform/darwin/docs/guides/For Style Authors.md.ejs
index d61b292148..857d03d6e7 100644
--- a/platform/darwin/docs/guides/For Style Authors.md.ejs
+++ b/platform/darwin/docs/guides/For Style Authors.md.ejs
@@ -379,11 +379,14 @@ In style specification | Method, function, or predicate type | Format string syn
 `%`                    | `modulus:by:` |
 `^`                    | `raise:toPower:` | `2 ** 2`
 `+`                    | `add:to:` | `1 + 2`
+`abs`                  | `abs:` | `abs(-1)`
 `acos`                 | |
 `asin`                 | |
 `atan`                 | |
+`ceil`                 | `ceiling:` | `ceiling(0.99999)`
 `cos`                  | |
 `e`                    | | `%@` representing `NSNumber` containing `M_E`
+`floor`                | `floor:` | `floor(-0.99999)`
 `ln`                   | `ln:` | `ln(2)`
 `ln2`                  | | `%@` representing `NSNumber` containing `M_LN2`
 `log10`                | `log:` | `log(1)`
@@ -391,6 +394,7 @@ In style specification | Method, function, or predicate type | Format string syn
 `max`                  | `max:` | `max({1, 2, 2, 3, 4, 7, 9})`
 `min`                  | `min:` | `min({1, 2, 2, 3, 4, 7, 9})`
 `pi`                   | | `%@` representing `NSNumber` containing `M_PI`
+`round`                | `mgl_round:` | `mgl_round(1.5)`
 `sin`                  | |
 `sqrt`                 | `sqrt:` | `sqrt(2)`
 `tan`                  | |
diff --git a/platform/darwin/docs/guides/Predicates and Expressions.md b/platform/darwin/docs/guides/Predicates and Expressions.md
index 13204b09a6..1b8714811d 100644
--- a/platform/darwin/docs/guides/Predicates and Expressions.md
+++ b/platform/darwin/docs/guides/Predicates and Expressions.md
@@ -196,6 +196,7 @@ Initializer parameter | Format string syntax | Description
 `mgl_interpolate:withCurveType:parameters:stops:` | `mgl_interpolate:withCurveType:parameters:stops:(x, 'linear', nil, %@)` | Produces continuous, smooth results by interpolating between pairs of input and output values (“stops”). Compared to the `mgl_interpolateWithCurveType:parameters:stops:` custom function, the input expression (that function’s target) is instead passed in as the first argument to this function.
 `mgl_step:from:stops:` | `mgl_step:from:stops:(x, 11, %@)` | Produces discrete, stepped results by evaluating a piecewise-constant function defined by pairs of input and output values ("stops"). Compared to the `mgl_stepWithMinimum:stops:` custom function, the input expression (that function’s target) is instead passed in as the first argument to this function.
 `mgl_join:` | `mgl_join({'Old', 'MacDonald'})` | Returns the result of concatenating together all the elements of an array in order. Compared to the `stringByAppendingString:` custom function, this function takes only one argument, which is an aggregate expression containing the strings to concatenate.
+`mgl_round:` | `mgl_round(1.5)` | Returns the number rounded to the nearest integer. If the number is halfway between two integers, this function rounds it away from zero.
 `mgl_coalesce:` | `mgl_coalesce({x, y, z})` | Returns the first non-`nil` value from an array of expressions.
 `MGL_LET` | `MGL_LET('age', uppercase('old'), 'name', uppercase('MacDonald'), mgl_join({$age, $name}))` | Any number of variable names interspersed with their assigned `NSExpression` values, followed by an `NSExpression` that may contain references to those variables. Compared to the `mgl_expressionWithContext:` custom function, this function takes the variable names and values inline before the expression that contains references to those variables.
 `MGL_MATCH` | `MGL_MATCH(x, 0, 'zero match', 1, 'one match', 'two match', 'default')` | Evaluates the first expression and returns the value that matches the initial condition. After the first expression condition a pair of matching/return value should be added and a default value.
diff --git a/platform/darwin/src/NSExpression+MGLAdditions.mm b/platform/darwin/src/NSExpression+MGLAdditions.mm
index 8c82c84c7d..6a61dd9abb 100644
--- a/platform/darwin/src/NSExpression+MGLAdditions.mm
+++ b/platform/darwin/src/NSExpression+MGLAdditions.mm
@@ -58,6 +58,7 @@
     // Install method-like functions, taking the number of arguments implied by
     // the selector name.
     INSTALL_METHOD(mgl_join:);
+    INSTALL_METHOD(mgl_round:);
     INSTALL_METHOD(mgl_interpolate:withCurveType:parameters:stops:);
     INSTALL_METHOD(mgl_step:from:stops:);
     INSTALL_METHOD(mgl_coalesce:);
@@ -84,6 +85,14 @@
 }
 
 /**
+ Rounds the given number to the nearest integer. If the number is halfway
+ between two integers, this method rounds it away from zero.
+ */
+- (NSNumber *)mgl_round:(NSNumber *)number {
+    return @(round(number.doubleValue));
+}
+
+/**
  A placeholder for a method that evaluates an interpolation expression.
  */
 - (id)mgl_interpolate:(id)inputExpression withCurveType:(NSString *)curveType parameters:(NSDictionary *)params stops:(NSDictionary *)stops {
@@ -487,6 +496,10 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
             @"sqrt": @"sqrt:",
             @"log10": @"log:",
             @"ln": @"ln:",
+            @"abs": @"abs:",
+            @"round": @"mgl_round:",
+            @"floor": @"floor:",
+            @"ceil": @"ceiling:",
             @"^": @"raise:toPower:",
             @"upcase": @"uppercase:",
             @"downcase": @"lowercase:",
@@ -720,9 +733,13 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
             @"log:": @"log10",
             @"ln:": @"ln",
             @"raise:toPower:": @"^",
+            @"ceiling:": @"ceil",
+            @"abs:": @"abs",
+            @"floor:": @"floor",
             @"uppercase:": @"upcase",
             @"lowercase:": @"downcase",
             @"length:": @"length",
+            @"mgl_round:": @"round",
             // Vararg aftermarket expressions need to be declared with an explicit and implicit first argument.
             @"MGL_LET": @"let",
             @"MGL_LET:": @"let",
@@ -826,18 +843,9 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
                 return [@[@"max"] arrayByAddingObjectsFromArray:arguments];
             } else if ([function isEqualToString:@"exp:"]) {
                 return [NSExpression expressionForFunction:@"raise:toPower:" arguments:@[@(M_E), self.arguments.firstObject]].mgl_jsonExpressionObject;
-            } else if ([function isEqualToString:@"ceiling:"]) {
-                return [NSExpression expressionWithFormat:@"trunc:(%@) + TERNARY(modulus:by:(%@, 1) > 0, 1, 0)",
-                        self.arguments.firstObject, self.arguments.firstObject].mgl_jsonExpressionObject;
             } else if ([function isEqualToString:@"trunc:"]) {
                 return [NSExpression expressionWithFormat:@"%@ - modulus:by:(%@, 1)",
                         self.arguments.firstObject, self.arguments.firstObject].mgl_jsonExpressionObject;
-            } else if ([function isEqualToString:@"abs:"]) {
-                return [NSExpression expressionWithFormat:@"%@ * TERNARY(%@ > 0, 1, -1)",
-                        self.arguments.firstObject, self.arguments.firstObject].mgl_jsonExpressionObject;
-            } else if ([function isEqualToString:@"floor:"]) {
-                return [NSExpression expressionWithFormat:@"trunc:(%@) - TERNARY(modulus:by:(%@, 1) < 0, 1, 0)",
-                        self.arguments.firstObject, self.arguments.firstObject].mgl_jsonExpressionObject;
             } else if ([function isEqualToString:@"mgl_join:"]) {
                 NSArray *arguments = [self.arguments.firstObject.collection valueForKeyPath:@"mgl_jsonExpressionObject"];
                 return [@[@"concat"] arrayByAddingObjectsFromArray:arguments];
diff --git a/platform/darwin/test/MGLExpressionTests.mm b/platform/darwin/test/MGLExpressionTests.mm
index 579d2505f2..236c8d1ad9 100644
--- a/platform/darwin/test/MGLExpressionTests.mm
+++ b/platform/darwin/test/MGLExpressionTests.mm
@@ -393,29 +393,25 @@ using namespace std::string_literals;
     }
     {
         NSExpression *expression = [NSExpression expressionForFunction:@"ceiling:" arguments:@[MGLConstantExpression(@1.5)]];
-        NSArray *jsonTruncation = @[@"-", @1.5, @[@"%", @1.5, @1]];
-        NSArray *jsonExpression = @[@"+", jsonTruncation, @[@"case", @[@">", @[@"%", @1.5, @1], @0], @1, @0]];
+        NSArray *jsonExpression = @[@"ceil", @1.5];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @2);
     }
     {
         NSExpression *expression = [NSExpression expressionForFunction:@"ceiling:" arguments:@[MGLConstantExpression(@-1.5)]];
-        NSArray *jsonTruncation = @[@"-", @-1.5, @[@"%", @-1.5, @1]];
-        NSArray *jsonExpression = @[@"+", jsonTruncation, @[@"case", @[@">", @[@"%", @-1.5, @1], @0], @1, @0]];
+        NSArray *jsonExpression = @[@"ceil", @-1.5];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @-1);
     }
     {
         NSExpression *expression = [NSExpression expressionForFunction:@"ceiling:" arguments:@[MGLConstantExpression(@2)]];
-        NSArray *jsonTruncation = @[@"-", @2, @[@"%", @2, @1]];
-        NSArray *jsonExpression = @[@"+", jsonTruncation, @[@"case", @[@">", @[@"%", @2, @1], @0], @1, @0]];
+        NSArray *jsonExpression = @[@"ceil", @2];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @2);
     }
     {
         NSExpression *expression = [NSExpression expressionForFunction:@"ceiling:" arguments:@[MGLConstantExpression(@-2)]];
-        NSArray *jsonTruncation = @[@"-", @-2, @[@"%", @-2, @1]];
-        NSArray *jsonExpression = @[@"+", jsonTruncation, @[@"case", @[@">", @[@"%", @-2, @1], @0], @1, @0]];
+        NSArray *jsonExpression = @[@"ceil", @-2];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @-2);
     }
@@ -433,44 +429,64 @@ using namespace std::string_literals;
     }
     {
         NSExpression *expression = [NSExpression expressionForFunction:@"abs:" arguments:@[MGLConstantExpression(@2)]];
-        NSArray *jsonExpression = @[@"*", @2, @[@"case", @[@">", @2, @0], @1, @-1]];
+        NSArray *jsonExpression = @[@"abs", @2];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @2);
     }
     {
         NSExpression *expression = [NSExpression expressionForFunction:@"abs:" arguments:@[MGLConstantExpression(@-2)]];
-        NSArray *jsonExpression = @[@"*", @-2, @[@"case", @[@">", @-2, @0], @1, @-1]];
+        NSArray *jsonExpression = @[@"abs", @-2];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @2);
     }
     {
         NSExpression *expression = [NSExpression expressionForFunction:@"floor:" arguments:@[MGLConstantExpression(@1.5)]];
-        NSArray *jsonTruncation = @[@"-", @1.5, @[@"%", @1.5, @1]];
-        NSArray *jsonExpression = @[@"-", jsonTruncation, @[@"case", @[@"<", @[@"%", @1.5, @1], @0], @1, @0]];
+        NSArray *jsonExpression = @[@"floor", @1.5];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @1);
     }
     {
         NSExpression *expression = [NSExpression expressionForFunction:@"floor:" arguments:@[MGLConstantExpression(@-1.5)]];
-        NSArray *jsonTruncation = @[@"-", @-1.5, @[@"%", @-1.5, @1]];
-        NSArray *jsonExpression = @[@"-", jsonTruncation, @[@"case", @[@"<", @[@"%", @-1.5, @1], @0], @1, @0]];
+        NSArray *jsonExpression = @[@"floor", @-1.5];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @-2);
     }
     {
         NSExpression *expression = [NSExpression expressionForFunction:@"floor:" arguments:@[MGLConstantExpression(@2)]];
-        NSArray *jsonTruncation = @[@"-", @2, @[@"%", @2, @1]];
-        NSArray *jsonExpression = @[@"-", jsonTruncation, @[@"case", @[@"<", @[@"%", @2, @1], @0], @1, @0]];
+        NSArray *jsonExpression = @[@"floor", @2];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @2);
     }
     {
         NSExpression *expression = [NSExpression expressionForFunction:@"floor:" arguments:@[MGLConstantExpression(@-2)]];
-        NSArray *jsonTruncation = @[@"-", @-2, @[@"%", @-2, @1]];
-        NSArray *jsonExpression = @[@"-", jsonTruncation, @[@"case", @[@"<", @[@"%", @-2, @1], @0], @1, @0]];
+        NSArray *jsonExpression = @[@"floor", @-2];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @-2);
     }
+    {
+        NSExpression *expression = [NSExpression expressionForFunction:@"mgl_round:" arguments:@[MGLConstantExpression(@1.5)]];
+        NSArray *jsonExpression = @[@"round", @1.5];
+        XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @2);
+    }
+    {
+        NSExpression *expression = [NSExpression expressionForFunction:@"mgl_round:" arguments:@[MGLConstantExpression(@-1.5)]];
+        NSArray *jsonExpression = @[@"round", @-1.5];
+        XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @-2);
+    }
+    {
+        NSExpression *expression = [NSExpression expressionForFunction:@"mgl_round:" arguments:@[MGLConstantExpression(@2.5)]];
+        NSArray *jsonExpression = @[@"round", @2.5];
+        XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @3);
+    }
+    {
+        NSExpression *expression = [NSExpression expressionForFunction:@"mgl_round:" arguments:@[MGLConstantExpression(@-2.5)]];
+        NSArray *jsonExpression = @[@"round", @-2.5];
+        XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @-3);
+    }
 }
 
 - (void)testTrigonometricExpressionObject {
diff --git a/platform/ios/docs/guides/For Style Authors.md b/platform/ios/docs/guides/For Style Authors.md
index 6b8839ecbe..87da59162e 100644
--- a/platform/ios/docs/guides/For Style Authors.md
+++ b/platform/ios/docs/guides/For Style Authors.md
@@ -364,11 +364,14 @@ In style specification | Method, function, or predicate type | Format string syn
 `%`                    | `modulus:by:` |
 `^`                    | `raise:toPower:` | `2 ** 2`
 `+`                    | `add:to:` | `1 + 2`
+`abs`                  | `abs:` | `abs(-1)`
 `acos`                 | |
 `asin`                 | |
 `atan`                 | |
+`ceil`                 | `ceiling:` | `ceiling(0.99999)`
 `cos`                  | |
 `e`                    | | `%@` representing `NSNumber` containing `M_E`
+`floor`                | `floor:` | `floor(-0.99999)`
 `ln`                   | `ln:` | `ln(2)`
 `ln2`                  | | `%@` representing `NSNumber` containing `M_LN2`
 `log10`                | `log:` | `log(1)`
@@ -376,6 +379,7 @@ In style specification | Method, function, or predicate type | Format string syn
 `max`                  | `max:` | `max({1, 2, 2, 3, 4, 7, 9})`
 `min`                  | `min:` | `min({1, 2, 2, 3, 4, 7, 9})`
 `pi`                   | | `%@` representing `NSNumber` containing `M_PI`
+`round`                | `mgl_round:` | `mgl_round(1.5)`
 `sin`                  | |
 `sqrt`                 | `sqrt:` | `sqrt(2)`
 `tan`                  | |
diff --git a/platform/macos/docs/guides/For Style Authors.md b/platform/macos/docs/guides/For Style Authors.md
index 8bd2e04d2b..e90858c664 100644
--- a/platform/macos/docs/guides/For Style Authors.md
+++ b/platform/macos/docs/guides/For Style Authors.md
@@ -357,11 +357,14 @@ In style specification | Method, function, or predicate type | Format string syn
 `%`                    | `modulus:by:` |
 `^`                    | `raise:toPower:` | `2 ** 2`
 `+`                    | `add:to:` | `1 + 2`
+`abs`                  | `abs:` | `abs(-1)`
 `acos`                 | |
 `asin`                 | |
 `atan`                 | |
+`ceil`                 | `ceiling:` | `ceiling(0.99999)`
 `cos`                  | |
 `e`                    | | `%@` representing `NSNumber` containing `M_E`
+`floor`                | `floor:` | `floor(-0.99999)`
 `ln`                   | `ln:` | `ln(2)`
 `ln2`                  | | `%@` representing `NSNumber` containing `M_LN2`
 `log10`                | `log:` | `log(1)`
@@ -369,6 +372,7 @@ In style specification | Method, function, or predicate type | Format string syn
 `max`                  | `max:` | `max({1, 2, 2, 3, 4, 7, 9})`
 `min`                  | `min:` | `min({1, 2, 2, 3, 4, 7, 9})`
 `pi`                   | | `%@` representing `NSNumber` containing `M_PI`
+`round`                | `mgl_round:` | `mgl_round(1.5)`
 `sin`                  | |
 `sqrt`                 | `sqrt:` | `sqrt(2)`
 `tan`                  | |
diff --git a/src/mbgl/style/expression/compound_expression.cpp b/src/mbgl/style/expression/compound_expression.cpp
index 77b294b380..c36ffa33e3 100644
--- a/src/mbgl/style/expression/compound_expression.cpp
+++ b/src/mbgl/style/expression/compound_expression.cpp
@@ -6,6 +6,7 @@
 #include <mbgl/util/ignore.hpp>
 #include <mbgl/util/string.hpp>
 #include <mbgl/util/platform.hpp>
+#include <cmath>
 
 namespace mbgl {
 namespace style {
@@ -362,6 +363,11 @@ std::unordered_map<std::string, CompoundExpressionRegistry::Definition> initiali
         return result;
     });
     
+    define("round", [](double x) -> Result<double> { return std::round(x); });
+    define("floor", [](double x) -> Result<double> { return std::floor(x); });
+    define("ceil", [](double x) -> Result<double> { return std::ceil(x); });
+    define("abs", [](double x) -> Result<double> { return std::abs(x); });
+
     define(">", [](double lhs, double rhs) -> Result<bool> { return lhs > rhs; });
     define(">", [](const std::string& lhs, const std::string& rhs) -> Result<bool> { return lhs > rhs; });
     define(">=", [](double lhs, double rhs) -> Result<bool> { return lhs >= rhs; });