From 328c4a13f1d63b02cbc7afe8e46a16ef4f896f07 Mon Sep 17 00:00:00 2001
From: Stephen Dolan <mu@netsoc.tcd.ie>
Date: Tue, 4 Sep 2012 16:05:24 +0100
Subject: [PATCH] Add "elif" to if-then-else constructs.

---
 c/lexer.l  |  1 +
 c/parser.y | 15 ++++++++++++---
 c/testdata |  5 +++++
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/c/lexer.l b/c/lexer.l
index e3c140b6..98365f1f 100644
--- a/c/lexer.l
+++ b/c/lexer.l
@@ -16,6 +16,7 @@
 "if" { return IF; }
 "then" { return THEN; }
 "else" { return ELSE; }
+"elif" { return ELSE_IF; }
 "end" { return END; }
 "//" { return DEFINEDOR; }
 "."|"="|";"|"["|"]"|","|":"|"("|")"|"{"|"}"|"|"|"+"|"\$" { return yytext[0];}
diff --git a/c/parser.y b/c/parser.y
index d4e8d8f4..165cdb42 100644
--- a/c/parser.y
+++ b/c/parser.y
@@ -32,6 +32,7 @@
 %token IF "if"
 %token THEN "then"
 %token ELSE "else"
+%token ELSE_IF "elif"
 %token END "end"
 %right "//"
 %nonassoc '=' SETPIPE
@@ -39,7 +40,7 @@
 %left '+'
 
 
-%type <blk> Exp Term MkDict MkDictPair ExpD
+%type <blk> Exp Term MkDict MkDictPair ExpD ElseBody
 
 %{
 #include "lexer.yy.h"
@@ -85,8 +86,8 @@ Term "as" '$' IDENT '|' Exp {
   jv_free($4);
 } |
 
-"if" Exp "then" Exp "else" Exp "end" {
-  $$ = gen_cond($2, $4, $6);
+"if" Exp "then" Exp ElseBody {
+  $$ = gen_cond($2, $4, $5);
 } |
 
 Exp '=' Exp {
@@ -128,6 +129,14 @@ Term {
   $$ = $1; 
 }
 
+ElseBody:
+"elif" Exp "then" Exp ElseBody {
+  $$ = gen_cond($2, $4, $5);
+} |
+"else" Exp "end" {
+  $$ = $2;
+}
+
 
 ExpD:
 ExpD '|' ExpD { 
diff --git a/c/testdata b/c/testdata
index 888d8b74..3fe231f5 100644
--- a/c/testdata
+++ b/c/testdata
@@ -243,6 +243,11 @@ def inc(x): x |= .+1; inc(.[].a)
 [{"foo":0},{"foo":1},{"foo":[]},{"foo":true},{"foo":false},{"foo":null},{"foo":"foo"},{}]
 ["yep","yep","yep","yep","nope","nope","yep","nope"]
 
+[.[] | if .baz then "strange" elif .foo then "yep" else "nope" end]
+[{"foo":0},{"foo":1},{"foo":[]},{"foo":true},{"foo":false},{"foo":null},{"foo":"foo"},{}]
+["yep","yep","yep","yep","nope","nope","yep","nope"]
+
+
 # FIXME: define/test behaviour of 'if (.foo,.bar) then A else B end'
 
 [.[] | [.foo[] // .bar]]