Add if statements

corpus/control_flow.txt

@@ -15,3 +15,31 @@ done
     (do_group
       (command (command_name) (argument))
       (command (command_name) (argument)))))
+
+====================================
+If statements
+====================================
+
+if cat some_file | grep -v ok; then
+  echo one
+elif cat other_file | grep -v ok; then
+  echo two
+else
+  exit
+fi
+
+---
+
+(program
+  (if_statement
+    (pipeline
+      (command (command_name) (argument))
+      (command (command_name) (argument) (argument)))
+    (command (command_name) (argument))
+    (elif_clause
+      (pipeline
+        (command (command_name) (argument))
+        (command (command_name) (argument) (argument)))
+      (command (command_name) (argument)))
+    (else_clause
+      (command (command_name)))))

grammar.js

@@ -26,6 +26,7 @@ module.exports = grammar({
     statement: $ => choice(
       $.command,
       $.while_statement,
+      $.if_statement,
       $.pipeline,
       $.list
     ),
@@ -36,6 +37,28 @@ module.exports = grammar({
       $.do_group
     ),
 
+    if_statement: $ => seq(
+      'if',
+      $._terminated_statement,
+      'then',
+      repeat($._terminated_statement),
+      repeat($.elif_clause),
+      optional($.else_clause),
+      'fi'
+    ),
+
+    elif_clause: $ => seq(
+      'elif',
+      $._terminated_statement,
+      'then',
+      repeat($._terminated_statement)
+    ),
+
+    else_clause: $ => seq(
+      'else',
+      repeat($._terminated_statement)
+    ),
+
     do_group: $ => seq(
       'do',
       repeat($._terminated_statement),

src/grammar.json

@@ -45,6 +45,10 @@
           "type": "SYMBOL",
           "name": "while_statement"
         },
+        {
+          "type": "SYMBOL",
+          "name": "if_statement"
+        },
         {
           "type": "SYMBOL",
           "name": "pipeline"
@@ -72,6 +76,93 @@
         }
       ]
     },
+    "if_statement": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "if"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "_terminated_statement"
+        },
+        {
+          "type": "STRING",
+          "value": "then"
+        },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "SYMBOL",
+            "name": "_terminated_statement"
+          }
+        },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "SYMBOL",
+            "name": "elif_clause"
+          }
+        },
+        {
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "SYMBOL",
+              "name": "else_clause"
+            },
+            {
+              "type": "BLANK"
+            }
+          ]
+        },
+        {
+          "type": "STRING",
+          "value": "fi"
+        }
+      ]
+    },
+    "elif_clause": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "elif"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "_terminated_statement"
+        },
+        {
+          "type": "STRING",
+          "value": "then"
+        },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "SYMBOL",
+            "name": "_terminated_statement"
+          }
+        }
+      ]
+    },
+    "else_clause": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "else"
+        },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "SYMBOL",
+            "name": "_terminated_statement"
+          }
+        }
+      ]
+    },
     "do_group": {
       "type": "SEQ",
       "members": [