Support optional else-branch for if-then-elif-end (#2598)

4 files changed, 376 insertions, 379 deletions

diff --git a/docs/content/manual/manual.yml b/docs/content/manual/manual.yml
index d5918be8..16d17c07 100644
--- a/docs/content/manual/manual.yml
+++ b/docs/content/manual/manual.yml
@@ -2147,7 +2147,7 @@ sections:
 
           `if A then B end` is the same as `if A then B else .  end`.
           That is, the `else` branch is optional, and if absent is the
-          same as `.`.
+          same as `.`. This also applies to `elif` with absent ending `else` branch.
 
           Checking for false or null is a simpler notion of
           "truthiness" than is found in JavaScript or Python, but it
diff --git a/src/parser.c b/src/parser.c
index 28d47c50..66469b5c 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -893,7 +893,7 @@ union yyalloc
 /* YYFINAL -- State number of the termination state.  */
 #define YYFINAL  27
 /* YYLAST -- Last index in YYTABLE.  */
-#define YYLAST   2143
+#define YYLAST   2093
 
 /* YYNTOKENS -- Number of terminals.  */
 #define YYNTOKENS  69
@@ -957,12 +957,12 @@ static const yytype_int8 yytranslate[] =
 static const yytype_int16 yyrline[] =
 {
        0,   306,   306,   309,   314,   317,   332,   335,   340,   343,
-     348,   352,   355,   359,   363,   367,   370,   373,   378,   382,
-     386,   391,   398,   402,   406,   410,   414,   418,   422,   426,
-     430,   434,   438,   442,   446,   450,   454,   458,   462,   468,
-     474,   478,   482,   486,   490,   494,   498,   502,   506,   511,
-     514,   531,   540,   547,   555,   566,   571,   577,   580,   585,
-     589,   593,   600,   600,   604,   604,   611,   614,   617,   623,
+     348,   352,   355,   359,   363,   367,   370,   375,   379,   383,
+     388,   395,   399,   403,   407,   411,   415,   419,   423,   427,
+     431,   435,   439,   443,   447,   451,   455,   459,   465,   471,
+     475,   479,   483,   487,   491,   495,   499,   503,   508,   511,
+     528,   537,   544,   552,   563,   568,   574,   577,   582,   586,
+     590,   597,   597,   601,   601,   608,   611,   614,   620,   623,
      626,   631,   634,   637,   643,   646,   649,   657,   661,   664,
      667,   670,   673,   676,   679,   682,   685,   689,   695,   698,
      701,   704,   707,   710,   713,   716,   719,   722,   725,   728,
@@ -1031,35 +1031,35 @@ static const yytype_int16 yypact[] =
       13,   775,    14,    49,   -55,    11,  -120,     7,  -120,    32,
      775,   508,   508,   775,    19,     2,  -120,   775,   525,   887,
      292,   458,   358,  1391,   775,  -120,     6,  -120,    -3,    -3,
-     775,    49,   683,   775,  -120,  -120,    52,  1797,     8,    10,
+     775,    49,   683,   775,  -120,  -120,    52,  1747,     8,    10,
       48,    79,  -120,   106,  -120,    66,    50,  1221,  -120,  -120,
     -120,  -120,  -120,  -120,  -120,  -120,  -120,  -120,  -120,  -120,
     -120,  -120,  -120,  -120,  -120,  -120,  -120,  -120,    61,  -120,
     -120,   124,     7,    68,    62,  -120,   968,   -22,    64,   775,
-    2084,    69,    71,    63,    87,   775,   775,   775,   775,   775,
+    2034,    69,    71,    63,    87,   775,   775,   775,   775,   775,
      775,   775,   775,   775,   775,   775,   775,   775,   775,   775,
      775,   775,   775,   775,   775,   775,   775,   775,   775,  -120,
-    -120,  1965,    78,   -20,    15,   169,   125,  -120,  -120,  -120,
-    1965,   775,  -120,  -120,  1442,  1965,   -10,  -120,  -120,    -2,
+    -120,  1915,    78,   -20,    15,   169,   125,  -120,  -120,  -120,
+    1915,   775,  -120,  -120,  1442,  1915,   -10,  -120,  -120,    -2,
      775,   590,   -20,   -20,   655,    90,  -120,    12,  -120,  -120,
       77,  -120,  -120,  -120,  -120,   415,   443,  -120,   443,  1255,
-      81,  -120,   443,   443,  -120,   415,  1999,   353,   353,   214,
-     571,  2031,  1999,  1999,  1999,  1999,  1999,  1999,   353,   353,
-    1965,   214,  1999,   353,   353,    66,    66,    82,    82,    82,
+      81,  -120,   443,   443,  -120,   415,  1949,   353,   353,   214,
+     571,  1981,  1949,  1949,  1949,  1949,  1949,  1949,   353,   353,
+    1915,   214,  1949,   353,   353,    66,    66,    82,    82,    82,
     -120,   138,   -20,   837,   105,    99,   113,   775,    96,    93,
      775,   103,   918,    20,  -120,  -120,   775,  -120,    16,  -120,
-    2112,    18,  -120,  1493,  -120,  1697,   102,   104,  -120,  -120,
+    2062,    18,  -120,  1493,  -120,  1697,   102,   104,  -120,  -120,
      775,  -120,   775,  -120,   159,   -11,  -120,   443,   119,     3,
      119,   108,   443,   119,   119,  -120,  -120,  -120,   -13,   109,
      115,   775,   163,   116,   -38,  -120,   118,   -20,   775,  1018,
     -120,  -120,  1068,  -120,   747,   110,  -120,   165,  -120,  -120,
     -120,  -120,    -2,   121,  -120,   775,   775,  -120,  -120,   775,
-     775,  1965,  1831,  -120,  -120,   443,   443,   119,   -20,  -120,
-     -20,   -20,  1289,   122,   -20,   837,  -120,   -20,   150,  1965,
-     136,   139,   142,  1118,  -120,  -120,  -120,   775,  1881,  1931,
+     775,  1915,  1781,  -120,  -120,   443,   443,   119,   -20,  -120,
+     -20,   -20,  1289,   122,   -20,   837,  -120,   -20,   150,  1915,
+     136,   139,   142,  1118,  -120,  -120,  -120,   775,  1831,  1881,
     1544,  1595,  -120,   119,   119,  -120,  -120,  -120,   140,   -20,
     -120,  -120,  -120,  -120,  -120,  -120,   143,  1646,  -120,   775,
-     775,   775,   -20,  -120,  -120,  -120,  1747,  1323,  1168,  -120,
+     775,   775,   -20,  -120,  -120,  -120,  1697,  1323,  1168,  -120,
     -120,  -120,   775,  -120,  1357,  -120
 };
 
@@ -1069,38 +1069,38 @@ static const yytype_int16 yypact[] =
 static const yytype_uint8 yydefact[] =
 {
        4,     0,     0,     6,   110,    83,   100,   102,    75,     0,
-       0,     0,     0,     0,     0,     0,    62,     0,     0,     0,
-       0,     0,     0,     0,     0,   101,    48,     1,     0,     0,
-       8,     6,     0,     0,    79,    64,     0,     0,     0,     0,
-      19,     0,    77,     0,    66,    33,     0,     0,   108,   137,
+       0,     0,     0,     0,     0,     0,    61,     0,     0,     0,
+       0,     0,     0,     0,     0,   101,    47,     1,     0,     0,
+       8,     6,     0,     0,    79,    63,     0,     0,     0,     0,
+      18,     0,    77,     0,    65,    32,     0,     0,   108,   137,
      138,   139,   140,   141,   142,   143,   144,   145,   146,   147,
      148,   149,   150,   151,   152,   153,   154,   155,     0,   109,
       86,     0,     0,    85,     0,   105,     0,     0,   167,     0,
        0,   163,   168,     0,   157,     0,     0,     0,     0,     0,
        0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
-       0,     0,     0,     0,     0,     0,     0,     0,     0,    22,
-       5,    10,    82,     0,     0,     0,     0,    54,    53,     3,
-       2,     8,     7,    49,     0,   118,     0,   116,    66,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,     0,    21,
+       5,    10,    82,     0,     0,     0,     0,    53,    52,     3,
+       2,     8,     7,    48,     0,   118,     0,   116,    65,     0,
        0,     0,     0,     0,     0,     0,    76,     0,   112,   103,
        0,    87,    81,   113,   104,     0,     0,   115,     0,     0,
-     165,   166,     0,     0,   106,     0,    41,    42,    43,    26,
-      25,    24,    28,    32,    35,    37,    40,    27,    46,    47,
-      29,    30,    23,    44,    45,    31,    34,    36,    38,    39,
+     165,   166,     0,     0,   106,     0,    40,    41,    42,    25,
+      24,    23,    27,    31,    34,    36,    39,    26,    45,    46,
+      28,    29,    22,    43,    44,    30,    33,    35,    37,    38,
       78,     0,     0,     0,     0,     0,   122,     0,    84,     0,
-       0,    93,     0,     0,     9,    50,     0,   111,     0,    61,
-       0,     0,    57,     0,    17,     0,     0,     0,    20,    18,
-       0,    67,     0,    63,     0,     0,   159,     0,   170,    73,
+       0,    93,     0,     0,     9,    49,     0,   111,     0,    60,
+       0,     0,    56,     0,    16,     0,     0,     0,    19,    17,
+       0,    66,     0,    62,     0,     0,   159,     0,   170,    73,
      160,     0,     0,   162,   161,   158,   123,   126,     0,     0,
        0,     0,     0,     0,     0,   128,     0,     0,     0,     0,
-      80,   114,     0,    92,     0,    89,    52,     0,   117,    65,
-      59,    60,     0,     0,    55,     0,     0,    16,    15,     0,
-       0,    21,     0,   107,    72,     0,     0,   164,     0,   124,
+      80,   114,     0,    92,     0,    89,    51,     0,   117,    64,
+      58,    59,     0,     0,    54,     0,     0,    70,    15,     0,
+       0,    20,     0,   107,    72,     0,     0,   164,     0,   124,
        0,     0,     0,   130,     0,     0,   125,     0,   121,    11,
-      91,    99,    98,     0,    88,    51,    58,     0,     0,     0,
-       0,     0,    68,    71,   169,   127,   136,   132,     0,     0,
-     134,   129,   133,    90,    96,    95,    97,     0,    70,     0,
-       0,     0,     0,   131,    94,    56,     0,     0,     0,   135,
-      69,    12,     0,    14,     0,    13
+      91,    99,    98,     0,    88,    50,    57,     0,     0,     0,
+       0,     0,    67,    71,   169,   127,   136,   132,     0,     0,
+     134,   129,   133,    90,    96,    95,    97,     0,    69,     0,
+       0,     0,     0,   131,    94,    55,     0,     0,     0,   135,
+      68,    12,     0,    14,     0,    13
 };
 
 /* YYPGOTO[NTERM-NUM].  */
@@ -1300,11 +1300,6 @@ static const yytype_int16 yytable[] =
       92,    93,    94,    95,    96,    97,    98,     0,     0,     0,
        0,     0,     0,     0,    99,   100,   101,   102,   103,   104,
      105,   106,   107,   108,     0,   109,    85,    86,    87,    88,
-       0,     0,     0,     0,     0,     0,     0,   255,   256,     0,
-       0,     0,    89,    90,     0,     0,     0,     0,     0,    91,
-      92,    93,    94,    95,    96,    97,    98,     0,     0,     0,
-       0,     0,     0,     0,    99,   100,   101,   102,   103,   104,
-     105,   106,   107,   108,     0,   109,    85,    86,    87,    88,
        0,     0,     0,     0,     0,     0,   131,     0,     0,     0,
        0,     0,    89,    90,     0,     0,     0,     0,     0,    91,
       92,    93,    94,    95,    96,    97,    98,     0,     0,     0,
@@ -1519,11 +1514,6 @@ static const yytype_int16 yycheck[] =
       33,    34,    35,    36,    37,    38,    39,    -1,    -1,    -1,
       -1,    -1,    -1,    -1,    47,    48,    49,    50,    51,    52,
       53,    54,    55,    56,    -1,    58,     9,    10,    11,    12,
-      -1,    -1,    -1,    -1,    -1,    -1,    -1,    20,    21,    -1,
-      -1,    -1,    25,    26,    -1,    -1,    -1,    -1,    -1,    32,
-      33,    34,    35,    36,    37,    38,    39,    -1,    -1,    -1,
-      -1,    -1,    -1,    -1,    47,    48,    49,    50,    51,    52,
-      53,    54,    55,    56,    -1,    58,     9,    10,    11,    12,
       -1,    -1,    -1,    -1,    -1,    -1,    19,    -1,    -1,    -1,
       -1,    -1,    25,    26,    -1,    -1,    -1,    -1,    -1,    32,
       33,    34,    35,    36,    37,    38,    39,    -1,    -1,    -1,
@@ -1606,9 +1596,9 @@ static const yytype_int8 yyr1[] =
       74,    74,    74,    74,    74,    74,    74,    74,    74,    74,
       74,    74,    74,    74,    74,    74,    74,    74,    74,    74,
       74,    74,    74,    74,    74,    74,    74,    74,    74,    74,
-      74,    74,    74,    74,    74,    74,    74,    74,    74,    75,
-      75,    76,    76,    76,    77,    78,    78,    79,    79,    80,
-      80,    80,    82,    81,    83,    81,    84,    84,    84,    85,
+      74,    74,    74,    74,    74,    74,    74,    74,    75,    75,
+      76,    76,    76,    77,    78,    78,    79,    79,    80,    80,
+      80,    82,    81,    83,    81,    84,    84,    84,    85,    85,
       85,    86,    86,    86,    87,    87,    87,    87,    87,    87,
       87,    87,    87,    87,    87,    87,    87,    87,    87,    87,
       87,    87,    87,    87,    87,    87,    87,    87,    87,    87,
@@ -1626,13 +1616,13 @@ static const yytype_int8 yyr1[] =
 static const yytype_int8 yyr2[] =
 {
        0,     2,     3,     3,     0,     3,     0,     2,     0,     2,
-       2,     5,     9,    11,     9,     5,     5,     4,     4,     2,
-       4,     5,     2,     3,     3,     3,     3,     3,     3,     3,
-       3,     3,     3,     2,     3,     3,     3,     3,     3,     3,
-       3,     3,     3,     3,     3,     3,     3,     3,     1,     2,
-       3,     5,     4,     2,     1,     5,     8,     1,     3,     2,
-       2,     1,     0,     4,     0,     5,     0,     2,     4,     5,
-       3,     3,     2,     1,     1,     1,     3,     2,     3,     2,
+       2,     5,     9,    11,     9,     5,     4,     4,     2,     4,
+       5,     2,     3,     3,     3,     3,     3,     3,     3,     3,
+       3,     3,     2,     3,     3,     3,     3,     3,     3,     3,
+       3,     3,     3,     3,     3,     3,     3,     1,     2,     3,
+       5,     4,     2,     1,     5,     8,     1,     3,     2,     2,
+       1,     0,     4,     0,     5,     0,     2,     4,     5,     3,
+       1,     3,     2,     1,     1,     1,     3,     2,     3,     2,
        4,     3,     2,     1,     3,     2,     2,     3,     5,     4,
        6,     5,     4,     3,     7,     6,     6,     6,     5,     5,
        1,     1,     1,     3,     3,     2,     3,     5,     2,     2,
@@ -2212,187 +2202,187 @@ yydestruct (const char *yymsg,
     case YYSYMBOL_IDENT: /* IDENT  */
 #line 36 "src/parser.y"
             { jv_free(((*yyvaluep).literal)); }
-#line 2216 "src/parser.c"
+#line 2206 "src/parser.c"
         break;
 
     case YYSYMBOL_FIELD: /* FIELD  */
 #line 36 "src/parser.y"
             { jv_free(((*yyvaluep).literal)); }
-#line 2222 "src/parser.c"
+#line 2212 "src/parser.c"
         break;
 
     case YYSYMBOL_LITERAL: /* LITERAL  */
 #line 36 "src/parser.y"
             { jv_free(((*yyvaluep).literal)); }
-#line 2228 "src/parser.c"
+#line 2218 "src/parser.c"
         break;
 
     case YYSYMBOL_FORMAT: /* FORMAT  */
 #line 36 "src/parser.y"
             { jv_free(((*yyvaluep).literal)); }
-#line 2234 "src/parser.c"
+#line 2224 "src/parser.c"
         break;
 
     case YYSYMBOL_QQSTRING_TEXT: /* QQSTRING_TEXT  */
 #line 36 "src/parser.y"
             { jv_free(((*yyvaluep).literal)); }
-#line 2240 "src/parser.c"
+#line 2230 "src/parser.c"
         break;
 
     case YYSYMBOL_Module: /* Module  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2246 "src/parser.c"
+#line 2236 "src/parser.c"
         break;
 
     case YYSYMBOL_Imports: /* Imports  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2252 "src/parser.c"
+#line 2242 "src/parser.c"
         break;
 
     case YYSYMBOL_FuncDefs: /* FuncDefs  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2258 "src/parser.c"
+#line 2248 "src/parser.c"
         break;
 
     case YYSYMBOL_Exp: /* Exp  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2264 "src/parser.c"
+#line 2254 "src/parser.c"
         break;
 
     case YYSYMBOL_Import: /* Import  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2270 "src/parser.c"
+#line 2260 "src/parser.c"
         break;
 
     case YYSYMBOL_ImportWhat: /* ImportWhat  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2276 "src/parser.c"
+#line 2266 "src/parser.c"
         break;
 
     case YYSYMBOL_ImportFrom: /* ImportFrom  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2282 "src/parser.c"
+#line 2272 "src/parser.c"
         break;
 
     case YYSYMBOL_FuncDef: /* FuncDef  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2288 "src/parser.c"
+#line 2278 "src/parser.c"
         break;
 
     case YYSYMBOL_Params: /* Params  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2294 "src/parser.c"
+#line 2284 "src/parser.c"
         break;
 
     case YYSYMBOL_Param: /* Param  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2300 "src/parser.c"
+#line 2290 "src/parser.c"
         break;
 
     case YYSYMBOL_String: /* String  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2306 "src/parser.c"
+#line 2296 "src/parser.c"
         break;
 
     case YYSYMBOL_QQString: /* QQString  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2312 "src/parser.c"
+#line 2302 "src/parser.c"
         break;
 
     case YYSYMBOL_ElseBody: /* ElseBody  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2318 "src/parser.c"
+#line 2308 "src/parser.c"
         break;
 
     case YYSYMBOL_ExpD: /* ExpD  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2324 "src/parser.c"
+#line 2314 "src/parser.c"
         break;
 
     case YYSYMBOL_Term: /* Term  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2330 "src/parser.c"
+#line 2320 "src/parser.c"
         break;
 
     case YYSYMBOL_Args: /* Args  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2336 "src/parser.c"
+#line 2326 "src/parser.c"
         break;
 
     case YYSYMBOL_Arg: /* Arg  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2342 "src/parser.c"
+#line 2332 "src/parser.c"
         break;
 
     case YYSYMBOL_RepPatterns: /* RepPatterns  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2348 "src/parser.c"
+#line 2338 "src/parser.c"
         break;
 
     case YYSYMBOL_Patterns: /* Patterns  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2354 "src/parser.c"
+#line 2344 "src/parser.c"
         break;
 
     case YYSYMBOL_Pattern: /* Pattern  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2360 "src/parser.c"
+#line 2350 "src/parser.c"
         break;
 
     case YYSYMBOL_ArrayPats: /* ArrayPats  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2366 "src/parser.c"
+#line 2356 "src/parser.c"
         break;
 
     case YYSYMBOL_ObjPats: /* ObjPats  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2372 "src/parser.c"
+#line 2362 "src/parser.c"
         break;
 
     case YYSYMBOL_ObjPat: /* ObjPat  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2378 "src/parser.c"
+#line 2368 "src/parser.c"
         break;
 
     case YYSYMBOL_Keyword: /* Keyword  */
 #line 36 "src/parser.y"
             { jv_free(((*yyvaluep).literal)); }
-#line 2384 "src/parser.c"
+#line 2374 "src/parser.c"
         break;
 
     case YYSYMBOL_MkDict: /* MkDict  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2390 "src/parser.c"
+#line 2380 "src/parser.c"
         break;
 
     case YYSYMBOL_MkDictPair: /* MkDictPair  */
 #line 37 "src/parser.y"
             { block_free(((*yyvaluep).blk)); }
-#line 2396 "src/parser.c"
+#line 2386 "src/parser.c"
         break;
 
       default:
@@ -2700,7 +2690,7 @@ yyreduce:
                    {
   *answer = BLOCK((yyvsp[-2].blk), (yyvsp[-1].blk), gen_op_simple(TOP), (yyvsp[0].blk));
 }
-#line 2704 "src/parser.c"
+#line 2694 "src/parser.c"
     break;
 
   case 3: /* TopLevel: Module Imports FuncDefs  */
@@ -2708,7 +2698,7 @@ yyreduce:
                         {
   *answer = BLOCK((yyvsp[-2].blk), (yyvsp[-1].blk), (yyvsp[0].blk));
 }
-#line 2712 "src/parser.c"
+#line 2702 "src/parser.c"
     break;
 
   case 4: /* Module: %empty  */
@@ -2716,7 +2706,7 @@ yyreduce:
        {
   (yyval.blk) = gen_noop();
 }
-#line 2720 "src/parser.c"
+#line 2710 "src/parser.c"
     break;
 
   case 5: /* Module: "module" Exp ';'  */
@@ -2734,7 +2724,7 @@ yyreduce:
     (yyval.blk) = gen_module((yyvsp[-1].blk));
   }
 }
-#line 2738 "src/parser.c"
+#line 2728 "src/parser.c"
     break;
 
   case 6: /* Imports: %empty  */
@@ -2742,7 +2732,7 @@ yyreduce:
        {
   (yyval.blk) = gen_noop();
 }
-#line 2746 "src/parser.c"
+#line 2736 "src/parser.c"
     break;
 
   case 7: /* Imports: Import Imports  */
@@ -2750,7 +2740,7 @@ yyreduce:
                {
   (yyval.blk) = BLOCK((yyvsp[-1].blk), (yyvsp[0].blk));
 }
-#line 2754 "src/parser.c"
+#line 2744 "src/parser.c"
     break;
 
   case 8: /* FuncDefs: %empty  */
@@ -2758,7 +2748,7 @@ yyreduce:
        {
   (yyval.blk) = gen_noop();
 }
-#line 2762 "src/parser.c"
+#line 2752 "src/parser.c"
     break;
 
   case 9: /* FuncDefs: FuncDef FuncDefs  */
@@ -2766,7 +2756,7 @@ yyreduce:
                  {
   (yyval.blk) = block_join((yyvsp[-1].blk), (yyvsp[0].blk));
 }
-#line 2770 "src/parser.c"
+#line 2760 "src/parser.c"
     break;
 
   case 10: /* Exp: FuncDef Exp  */
@@ -2774,7 +2764,7 @@ yyreduce:
                           {
   (yyval.blk) = block_bind_referenced((yyvsp[-1].blk), (yyvsp[0].blk), OP_IS_CALL_PSEUDO);
 }
-#line 2778 "src/parser.c"
+#line 2768 "src/parser.c"
     break;
 
   case 11: /* Exp: Term "as" Patterns '|' Exp  */
@@ -2782,7 +2772,7 @@ yyreduce:
                            {
   (yyval.blk) = gen_destructure((yyvsp[-4].blk), (yyvsp[-2].blk), (yyvsp[0].blk));
 }
-#line 2786 "src/parser.c"
+#line 2776 "src/parser.c"
     break;
 
   case 12: /* Exp: "reduce" Term "as" Patterns '(' Exp ';' Exp ')'  */
@@ -2790,7 +2780,7 @@ yyreduce:
                                                 {
   (yyval.blk) = gen_reduce((yyvsp[-7].blk), (yyvsp[-5].blk), (yyvsp[-3].blk), (yyvsp[-1].blk));
 }
-#line 2794 "src/parser.c"
+#line 2784 "src/parser.c"
     break;
 
   case 13: /* Exp: "foreach" Term "as" Patterns '(' Exp ';' Exp ';' Exp ')'  */
@@ -2798,7 +2788,7 @@ yyreduce:
                                                          {
   (yyval.blk) = gen_foreach((yyvsp[-9].blk), (yyvsp[-7].blk), (yyvsp[-5].blk), (yyvsp[-3].blk), (yyvsp[-1].blk));
 }
-#line 2802 "src/parser.c"
+#line 2792 "src/parser.c"
     break;
 
   case 14: /* Exp: "foreach" Term "as" Patterns '(' Exp ';' Exp ')'  */
@@ -2806,7 +2796,7 @@ yyreduce:
                                                  {
   (yyval.blk) = gen_foreach((yyvsp[-7].blk), (yyvsp[-5].blk), (yyvsp[-3].blk), (yyvsp[-1].blk), gen_noop());
 }
-#line 2810 "src/parser.c"
+#line 2800 "src/parser.c"
     break;
 
   case 15: /* Exp: "if" Exp "then" Exp ElseBody  */
@@ -2814,294 +2804,286 @@ yyreduce:
                              {
   (yyval.blk) = gen_cond((yyvsp[-3].blk), (yyvsp[-1].blk), (yyvsp[0].blk));
 }
-#line 2818 "src/parser.c"
+#line 2808 "src/parser.c"
     break;
 
-  case 16: /* Exp: "if" Exp "then" Exp "end"  */
+  case 16: /* Exp: "if" Exp "then" error  */
 #line 370 "src/parser.y"
-                          {
-  (yyval.blk) = gen_cond((yyvsp[-3].blk), (yyvsp[-1].blk), gen_noop());
-}
-#line 2826 "src/parser.c"
-    break;
-
-  case 17: /* Exp: "if" Exp "then" error  */
-#line 373 "src/parser.y"
                       {
   FAIL((yyloc), "Possibly unterminated 'if' statement");
   (yyval.blk) = (yyvsp[-2].blk);
 }
-#line 2835 "src/parser.c"
+#line 2817 "src/parser.c"
     break;
 
-  case 18: /* Exp: "try" Exp "catch" Exp  */
-#line 378 "src/parser.y"
+  case 17: /* Exp: "try" Exp "catch" Exp  */
+#line 375 "src/parser.y"
                       {
   //$$ = BLOCK(gen_op_target(FORK_OPT, $2), $2, $4);
   (yyval.blk) = gen_try((yyvsp[-2].blk), gen_try_handler((yyvsp[0].blk)));
 }
-#line 2844 "src/parser.c"
+#line 2826 "src/parser.c"
     break;
 
-  case 19: /* Exp: "try" Exp  */
-#line 382 "src/parser.y"
+  case 18: /* Exp: "try" Exp  */
+#line 379 "src/parser.y"
           {
   //$$ = BLOCK(gen_op_target(FORK_OPT, $2), $2, gen_op_simple(BACKTRACK));
   (yyval.blk) = gen_try((yyvsp[0].blk), gen_op_simple(BACKTRACK));
 }
-#line 2853 "src/parser.c"
+#line 2835 "src/parser.c"
     break;
 
-  case 20: /* Exp: "try" Exp "catch" error  */
-#line 386 "src/parser.y"
+  case 19: /* Exp: "try" Exp "catch" error  */
+#line 383 "src/parser.y"
                         {
   FAIL((yyloc), "Possibly unterminated 'try' statement");
   (yyval.blk) = (yyvsp[-2].blk);
 }
-#line 2862 "src/parser.c"
+#line 2844 "src/parser.c"
     break;
 
-  case 21: /* Exp: "label" '$' IDENT '|' Exp  */
-#line 391 "src/parser.y"
+  case 20: /* Exp: "label" '$' IDENT '|' Exp  */
+#line 388 "src/parser.y"
                           {
   jv v = jv_string_fmt("*label-%s", jv_string_value((yyvsp[-2].literal)));
   (yyval.blk) = gen_location((yyloc), locations, gen_label(jv_string_value(v), (yyvsp[0].blk)));
   jv_free((yyvsp[-2].literal));
   jv_free(v);
 }
-#line 2873 "src/parser.c"
+#line 2855 "src/parser.c"
     break;
 
-  case 22: /* Exp: Exp '?'  */
-#line 398 "src/parser.y"
+  case 21: /* Exp: Exp '?'  */
+#line 395 "src/parser.y"
         {
   (yyval.blk) = gen_try((yyvsp[-1].blk), gen_op_simple(BACKTRACK));
 }
-#line 2881 "src/parser.c"
+#line 2863 "src/parser.c"
     break;
 
-  case 23: /* Exp: Exp '=' Exp  */
-#line 402 "src/parser.y"
+  case 22: /* Exp: Exp '=' Exp  */
+#line 399 "src/parser.y"
             {
   (yyval.blk) = gen_call("_assign", BLOCK(gen_lambda((yyvsp[-2].blk)), gen_lambda((yyvsp[0].blk))));
 }
-#line 2889 "src/parser.c"
+#line 2871 "src/parser.c"
     break;
 
-  case 24: /* Exp: Exp "or" Exp  */
-#line 406 "src/parser.y"
+  case 23: /* Exp: Exp "or" Exp  */
+#line 403 "src/parser.y"
              {
   (yyval.blk) = gen_or((yyvsp[-2].blk), (yyvsp[0].blk));
 }
-#line 2897 "src/parser.c"
+#line 2879 "src/parser.c"
     break;
 
-  case 25: /* Exp: Exp "and" Exp  */
-#line 410 "src/parser.y"
+  case 24: /* Exp: Exp "and" Exp  */
+#line 407 "src/parser.y"
               {
   (yyval.blk) = gen_and((yyvsp[-2].blk), (yyvsp[0].blk));
 }
-#line 2905 "src/parser.c"
+#line 2887 "src/parser.c"
     break;
 
-  case 26: /* Exp: Exp "//" Exp  */
-#line 414 "src/parser.y"
+  case 25: /* Exp: Exp "//" Exp  */
+#line 411 "src/parser.y"
              {
   (yyval.blk) = gen_definedor((yyvsp[-2].blk), (yyvsp[0].blk));
 }
-#line 2913 "src/parser.c"
+#line 2895 "src/parser.c"
     break;
 
-  case 27: /* Exp: Exp "//=" Exp  */
-#line 418 "src/parser.y"
+  case 26: /* Exp: Exp "//=" Exp  */
+#line 415 "src/parser.y"
               {
   (yyval.blk) = gen_definedor_assign((yyvsp[-2].blk), (yyvsp[0].blk));
 }
-#line 2921 "src/parser.c"
+#line 2903 "src/parser.c"
     break;
 
-  case 28: /* Exp: Exp "|=" Exp  */
-#line 422 "src/parser.y"
+  case 27: /* Exp: Exp "|=" Exp  */
+#line 419 "src/parser.y"
              {
   (yyval.blk) = gen_call("_modify", BLOCK(gen_lambda((yyvsp[-2].blk)), gen_lambda((yyvsp[0].blk))));
 }
-#line 2929 "src/parser.c"
+#line 2911 "src/parser.c"
     break;
 
-  case 29: /* Exp: Exp '|' Exp  */
-#line 426 "src/parser.y"
+  case 28: /* Exp: Exp '|' Exp  */
+#line 423 "src/parser.y"
             {
   (yyval.blk) = block_join((yyvsp[-2].blk), (yyvsp[0].blk));
 }
-#line 2937 "src/parser.c"
+#line 2919 "src/parser.c"
     break;
 
-  case 30: /* Exp: Exp ',' Exp  */
-#line 430 "src/parser.y"
+  case 29: /* Exp: Exp ',' Exp  */
+#line 427 "src/parser.y"
             {
   (yyval.blk) = gen_both((yyvsp[-2].blk), (yyvsp[0].blk));
 }
-#line 2945 "src/parser.c"
+#line 2927 "src/parser.c"
     break;
 
-  case 31: /* Exp: Exp '+' Exp  */
-#line 434 "src/parser.y"
+  case 30: /* Exp: Exp '+' Exp  */
+#line 431 "src/parser.y"
             {
   (yyval.blk) = gen_binop((yyvsp[-2].blk), (yyvsp[0].blk), '+');
 }
-#line 2953 "src/parser.c"
+#line 2935 "src/parser.c"
     break;
 
-  case 32: /* Exp: Exp "+=" Exp  */
-#line 438 "src/parser.y"
+  case 31: /* Exp: Exp "+=" Exp  */
+#line 435 "src/parser.y"
              {
   (yyval.blk) = gen_update((yyvsp[-2].blk), (yyvsp[0].blk), '+');
 }
-#line 2961 "src/parser.c"
+#line 2943 "src/parser.c"
     break;
 
-  case 33: /* Exp: '-' Exp  */
-#line 442 "src/parser.y"
+  case 32: /* Exp: '-' Exp  */
+#line 439 "src/parser.y"
         {
   (yyval.blk) = BLOCK((yyvsp[0].blk), gen_call("_negate", gen_noop()));
 }
-#line 2969 "src/parser.c"
+#line 2951 "src/parser.c"
     break;
 
-  case 34: /* Exp: Exp '-' Exp  */
-#line 446 "src/parser.y"
+  case 33: /* Exp: Exp '-' Exp  */
+#line 443 "src/parser.y"
             {
   (yyval.blk) = gen_binop((yyvsp[-2].blk), (yyvsp[0].blk), '-');
 }
-#line 2977 "src/parser.c"
+#line 2959 "src/parser.c"
     break;
 
-  case 35: /* Exp: Exp "-=" Exp  */
-#line 450 "src/parser.y"
+  case 34: /* Exp: Exp "-=" Exp  */
+#line 447 "src/parser.y"
              {
   (yyval.blk) = gen_update((yyvsp[-2].blk), (yyvsp[0].blk), '-');
 }
-#line 2985 "src/parser.c"
+#line 2967 "src/parser.c"
     break;
 
-  case 36: /* Exp: Exp '*' Exp  */
-#line 454 "src/parser.y"
+  case 35: /* Exp: Exp '*' Exp  */
+#line 451 "src/parser.y"
             {
   (yyval.blk) = gen_binop((yyvsp[-2].blk), (yyvsp[0].blk), '*');
 }
-#line 2993 "src/parser.c"
+#line 2975 "src/parser.c"
     break;
 
-  case 37: /* Exp: Exp "*=" Exp  */
-#line 458 "src/parser.y"
+  case 36: /* Exp: Exp "*=" Exp  */
+#line 455 "src/parser.y"
              {
   (yyval.blk) = gen_update((yyvsp[-2].blk), (yyvsp[0].blk), '*');
 }
-#line 3001 "src/parser.c"
+#line 2983 "src/parser.c"
     break;
 
-  case 38: /* Exp: Exp '/' Exp  */
-#line 462 "src/parser.y"
+  case 37: /* Exp: Exp '/' Exp  */
+#line 459 "src/parser.y"
             {
   (yyval.blk) = gen_binop((yyvsp[-2].blk), (yyvsp[0].blk), '/');
   if (block_is_const_inf((yyval.blk)))
     FAIL((yyloc), "Division by zero?");
 }
-#line 3011 "src/parser.c"
+#line 2993 "src/parser.c"
     break;
 
-  case 39: /* Exp: Exp '%' Exp  */
-#line 468 "src/parser.y"
+  case 38: /* Exp: Exp '%' Exp  */
+#line 465 "src/parser.y"
             {
   (yyval.blk) = gen_binop((yyvsp[-2].blk), (yyvsp[0].blk), '%');
   if (block_is_const_inf((yyval.blk)))
     FAIL((yyloc), "Remainder by zero?");
 }
-#line 3021 "src/parser.c"
+#line 3003 "src/parser.c"
     break;
 
-  case 40: /* Exp: Exp "/=" Exp  */
-#line 474 "src/parser.y"
+  case 39: /* Exp: Exp "/=" Exp  */
+#line 471 "src/parser.y"
              {
   (yyval.blk) = gen_update((yyvsp[-2].blk), (yyvsp[0].blk), '/');
 }
-#line 3029 "src/parser.c"
+#line 3011 "src/parser.c"
     break;
 
-  case 41: /* Exp: Exp "%=" Exp  */
-#line 478 "src/parser.y"
+  case 40: /* Exp: Exp "%=" Exp  */
+#line 475 "src/parser.y"
                {
   (yyval.blk) = gen_update((yyvsp[-2].blk), (yyvsp[0].blk), '%');
 }
-#line 3037 "src/parser.c"
+#line 3019 "src/parser.c"
     break;
 
-  case 42: /* Exp: Exp "==" Exp  */
-#line 482 "src/parser.y"
+  case 41: /* Exp: Exp "==" Exp  */
+#line 479 "src/parser.y"
              {
   (yyval.blk) = gen_binop((yyvsp[-2].blk), (yyvsp[0].blk), EQ);
 }
-#line 3045 "src/parser.c"
+#line 3027 "src/parser.c"
     break;
 
-  case 43: /* Exp: Exp "!=" Exp  */
-#line 486 "src/parser.y"
+  case 42: /* Exp: Exp "!=" Exp  */
+#line 483 "src/parser.y"
              {
   (yyval.blk) = gen_binop((yyvsp[-2].blk), (yyvsp[0].blk), NEQ);
 }
-#line 3053 "src/parser.c"
+#line 3035 "src/parser.c"
     break;
 
-  case 44: /* Exp: Exp '<' Exp  */
-#line 490 "src/parser.y"
+  case 43: /* Exp: Exp '<' Exp  */
+#line 487 "src/parser.y"
             {
   (yyval.blk) = gen_binop((yyvsp[-2].blk), (yyvsp[0].blk), '<');
 }
-#line 3061 "src/parser.c"
+#line 3043 "src/parser.c"
     break;
 
-  case 45: /* Exp: Exp '>' Exp  */
-#line 494 "src/parser.y"
+  case 44: /* Exp: Exp '>' Exp  */
+#line 491 "src/parser.y"
             {
   (yyval.blk) = gen_binop((yyvsp[-2].blk), (yyvsp[0].blk), '>');
 }
-#line 3069 "src/parser.c"
+#line 3051 "src/parser.c"
     break;
 
-  case 46: /* Exp: Exp "<=" Exp  */
-#line 498 "src/parser.y"
+  case 45: /* Exp: Exp "<=" Exp  */
+#line 495 "src/parser.y"
              {
   (yyval.blk) = gen_binop((yyvsp[-2].blk), (yyvsp[0].blk), LESSEQ);
 }
-#line 3077 "src/parser.c"
+#line 3059 "src/parser.c"
     break;
 
-  case 47: /* Exp: Exp ">=" Exp  */
-#line 502 "src/parser.y"
+  case 46: /* Exp: Exp ">=" Exp  */
+#line 499 "src/parser.y"
              {
   (yyval.blk) = gen_binop((yyvsp[-2].blk), (yyvsp[0].blk), GREATEREQ);
 }
-#line 3085 "src/parser.c"
+#line 3067 "src/parser.c"
     break;
 
-  case 48: /* Exp: Term  */
-#line 506 "src/parser.y"
+  case 47: /* Exp: Term  */
+#line 503 "src/parser.y"
      {
   (yyval.blk) = (yyvsp[0].blk);
 }
-#line 3093 "src/parser.c"
+#line 3075 "src/parser.c"
     break;
 
-  case 49: /* Import: ImportWhat ';'  */
-#line 511 "src/parser.y"
+  case 48: /* Import: ImportWhat ';'  */
+#line 508 "src/parser.y"
                {
   (yyval.blk) = (yyvsp[-1].blk);
 }
-#line 3101 "src/parser.c"
+#line 3083 "src/parser.c"
     break;
 
-  case 50: /* Import: ImportWhat Exp ';'  */
-#line 514 "src/parser.y"
+  case 49: /* Import: ImportWhat Exp ';'  */
+#line 511 "src/parser.y"
                    {
   if (!block_is_const((yyvsp[-1].blk))) {
     FAIL((yyloc), "Module metadata must be constant");
@@ -3117,11 +3099,11 @@ yyreduce:
     (yyval.blk) = gen_import_meta((yyvsp[-2].blk), (yyvsp[-1].blk));
   }
 }
-#line 3121 "src/parser.c"
+#line 3103 "src/parser.c"
     break;
 
-  case 51: /* ImportWhat: "import" ImportFrom "as" '$' IDENT  */
-#line 531 "src/parser.y"
+  case 50: /* ImportWhat: "import" ImportFrom "as" '$' IDENT  */
+#line 528 "src/parser.y"
                                    {
   jv v = block_const((yyvsp[-3].blk));
   // XXX Make gen_import take only blocks and the int is_data so we
@@ -3131,11 +3113,11 @@ yyreduce:
   jv_free((yyvsp[0].literal));
   jv_free(v);
 }
-#line 3135 "src/parser.c"
+#line 3117 "src/parser.c"
     break;
 
-  case 52: /* ImportWhat: "import" ImportFrom "as" IDENT  */
-#line 540 "src/parser.y"
+  case 51: /* ImportWhat: "import" ImportFrom "as" IDENT  */
+#line 537 "src/parser.y"
                                {
   jv v = block_const((yyvsp[-2].blk));
   (yyval.blk) = gen_import(jv_string_value(v), jv_string_value((yyvsp[0].literal)), 0);
@@ -3143,22 +3125,22 @@ yyreduce:
   jv_free((yyvsp[0].literal));
   jv_free(v);
 }
-#line 3147 "src/parser.c"
+#line 3129 "src/parser.c"
     break;
 
-  case 53: /* ImportWhat: "include" ImportFrom  */
-#line 547 "src/parser.y"
+  case 52: /* ImportWhat: "include" ImportFrom  */
+#line 544 "src/parser.y"
                      {
   jv v = block_const((yyvsp[0].blk));
   (yyval.blk) = gen_import(jv_string_value(v), NULL, 0);
   block_free((yyvsp[0].blk));
   jv_free(v);
 }
-#line 3158 "src/parser.c"
+#line 3140 "src/parser.c