add support for RobotFramework .robot files

lib/linguist/languages.yml

@@ -1187,6 +1187,12 @@ Rebol:
 Redcode:
   primary_extension: .cw
 
+RobotFramework:
+  type: programming
+  primary_extension: .robot
+  # extensions:
+  # - .txt
+
 Rouge:
   type: programming
   lexer: Clojure

samples/RobotFramework/data_driven.robot

@@ -0,0 +1,45 @@
+*** Settings ***
+Documentation     Example test cases using the data-driven testing approach.
+...
+...               Tests use `Calculate` keyword created in this file, that in
+...               turn uses keywords in `CalculatorLibrary`. An exception is
+...               the last test that has a custom _template keyword_.
+...
+...               The data-driven style works well when you need to repeat
+...               the same workflow multiple times.
+...
+...               Notice that one of these tests fails on purpose to show how
+...               failures look like.
+Test Template     Calculate
+Library           CalculatorLibrary
+
+*** Test Cases ***    Expression    Expected
+Addition              12 + 2 + 2    16
+                      2 + -3        -1
+
+Subtraction           12 - 2 - 2    8
+                      2 - -3        5
+
+Multiplication        12 * 2 * 2    48
+                      2 * -3        -6
+
+Division              12 / 2 / 2    3
+                      2 / -3        -1
+
+Failing               1 + 1         3
+
+Calculation error     [Template]    Calculation should fail
+                      kekkonen      Invalid button 'k'.
+                      ${EMPTY}      Invalid expression.
+                      1 / 0         Division by zero.
+
+*** Keywords ***
+Calculate
+    [Arguments]    ${expression}    ${expected}
+    Push buttons    C${expression}=
+    Result should be    ${expected}
+
+Calculation should fail
+    [Arguments]    ${expression}    ${expected}
+    ${error} =    Should cause error    C${expression}=
+    Should be equal    ${expected}    ${error}    # Using `BuiltIn` keyword

samples/RobotFramework/gherkin.robot

@@ -0,0 +1,33 @@
+*** Settings ***
+Documentation     Example test case using the gherkin syntax.
+...
+...               This test has a workflow similar to the keyword-driven
+...               examples. The difference is that the keywords use higher
+...               abstraction level and their arguments are embedded into
+...               the keyword names.
+...
+...               This kind of _gherkin_ syntax has been made popular by
+...               [http://cukes.info|Cucumber]. It works well especially when
+...               tests act as examples that need to be easily understood also
+...               by the business people.
+Library           CalculatorLibrary
+
+*** Test Cases ***
+Addition
+    Given calculator has been cleared
+    When user types "1 + 1"
+    and user pushes equals
+    Then result is "2"
+
+*** Keywords ***
+Calculator has been cleared
+    Push button    C
+
+User types "${expression}"
+    Push buttons    ${expression}
+
+User pushes equals
+    Push button    =
+
+Result is "${result}"
+    Result should be    ${result}

samples/RobotFramework/keyword_driven.robot

@@ -0,0 +1,37 @@
+*** Settings ***
+Documentation     Example test cases using the keyword-driven testing approach.
+...
+...               All tests contain a workflow constructed from keywords in
+...               `CalculatorLibrary`. Creating new tests or editing existing
+...               is easy even for people without programming skills.
+...
+...               This kind of style works well for normal test automation.
+...               If also business people need to understand tests, using
+...               _gherkin_ style may work better.
+Library           CalculatorLibrary
+
+*** Test Cases ***
+Push button
+    Push button    1
+    Result should be    1
+
+Push multiple buttons
+    Push button    1
+    Push button    2
+    Result should be    12
+
+Simple calculation
+    Push button    1
+    Push button    +
+    Push button    2
+    Push button    =
+    Result should be    3
+
+Longer calculation
+    Push buttons    5 + 4 - 3 * 2 / 1 =
+    Result should be    3
+
+Clear
+    Push button    1
+    Push button    C
+    Result should be    ${EMPTY}    # ${EMPTY} is a built-in variable