awk: after preinc/dec, only allow variable, field ref, array ref, or another preinc/dec

Accepting nonsense like "--4", and even "-- -4" is confusing.

function                                             old     new   delta
parse_expr                                           917     938     +21

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 69 insertions, 18 deletions

diff --git a/editors/awk.c b/editors/awk.c
index 48836298c..2563722f9 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -66,6 +66,8 @@
 #endif
 #ifndef debug_printf_parse
 # define debug_printf_parse(...) (fprintf(stderr, __VA_ARGS__))
+#else
+# define debug_parse_print_tc(...) ((void)0)
 #endif
 
 
@@ -210,13 +212,13 @@ typedef struct tsplitter_s {
 #define TC_SEQTERM      (1 << 1)                /* ) */
 #define TC_REGEXP       (1 << 2)                /* /.../ */
 #define TC_OUTRDR       (1 << 3)                /* | > >> */
-#define TC_UOPPOST      (1 << 4)                /* unary postfix operator */
-#define TC_UOPPRE1      (1 << 5)                /* unary prefix operator */
+#define TC_UOPPOST      (1 << 4)                /* unary postfix operator ++ -- */
+#define TC_UOPPRE1      (1 << 5)                /* unary prefix operator ++ -- $ */
 #define TC_BINOPX       (1 << 6)                /* two-opnd operator */
 #define TC_IN           (1 << 7)
 #define TC_COMMA        (1 << 8)
 #define TC_PIPE         (1 << 9)                /* input redirection pipe */
-#define TC_UOPPRE2      (1 << 10)               /* unary prefix operator */
+#define TC_UOPPRE2      (1 << 10)               /* unary prefix operator + - ! */
 #define TC_ARRTERM      (1 << 11)               /* ] */
 #define TC_GRPSTART     (1 << 12)               /* { */
 #define TC_GRPTERM      (1 << 13)               /* } */
@@ -243,14 +245,51 @@ typedef struct tsplitter_s {
 #define TC_STRING       (1 << 29)
 #define TC_NUMBER       (1 << 30)
 
-#define TC_UOPPRE  (TC_UOPPRE1 | TC_UOPPRE2)
+#ifndef debug_parse_print_tc
+#define debug_parse_print_tc(n) do { \
+if ((n) & TC_SEQSTART) debug_printf_parse(" SEQSTART"); \
+if ((n) & TC_SEQTERM ) debug_printf_parse(" SEQTERM" ); \
+if ((n) & TC_REGEXP  ) debug_printf_parse(" REGEXP"  ); \
+if ((n) & TC_OUTRDR  ) debug_printf_parse(" OUTRDR"  ); \
+if ((n) & TC_UOPPOST ) debug_printf_parse(" UOPPOST" ); \
+if ((n) & TC_UOPPRE1 ) debug_printf_parse(" UOPPRE1" ); \
+if ((n) & TC_BINOPX  ) debug_printf_parse(" BINOPX"  ); \
+if ((n) & TC_IN      ) debug_printf_parse(" IN"      ); \
+if ((n) & TC_COMMA   ) debug_printf_parse(" COMMA"   ); \
+if ((n) & TC_PIPE    ) debug_printf_parse(" PIPE"    ); \
+if ((n) & TC_UOPPRE2 ) debug_printf_parse(" UOPPRE2" ); \
+if ((n) & TC_ARRTERM ) debug_printf_parse(" ARRTERM" ); \
+if ((n) & TC_GRPSTART) debug_printf_parse(" GRPSTART"); \
+if ((n) & TC_GRPTERM ) debug_printf_parse(" GRPTERM" ); \
+if ((n) & TC_SEMICOL ) debug_printf_parse(" SEMICOL" ); \
+if ((n) & TC_NEWLINE ) debug_printf_parse(" NEWLINE" ); \
+if ((n) & TC_STATX   ) debug_printf_parse(" STATX"   ); \
+if ((n) & TC_WHILE   ) debug_printf_parse(" WHILE"   ); \
+if ((n) & TC_ELSE    ) debug_printf_parse(" ELSE"    ); \
+if ((n) & TC_BUILTIN ) debug_printf_parse(" BUILTIN" ); \
+if ((n) & TC_LENGTH  ) debug_printf_parse(" LENGTH"  ); \
+if ((n) & TC_GETLINE ) debug_printf_parse(" GETLINE" ); \
+if ((n) & TC_FUNCDECL) debug_printf_parse(" FUNCDECL"); \
+if ((n) & TC_BEGIN   ) debug_printf_parse(" BEGIN"   ); \
+if ((n) & TC_END     ) debug_printf_parse(" END"     ); \
+if ((n) & TC_EOF     ) debug_printf_parse(" EOF"     ); \
+if ((n) & TC_VARIABLE) debug_printf_parse(" VARIABLE"); \
+if ((n) & TC_ARRAY   ) debug_printf_parse(" ARRAY"   ); \
+if ((n) & TC_FUNCTION) debug_printf_parse(" FUNCTION"); \
+if ((n) & TC_STRING  ) debug_printf_parse(" STRING"  ); \
+if ((n) & TC_NUMBER  ) debug_printf_parse(" NUMBER"  ); \
+} while (0)
+#endif
 
 /* combined token classes */
+#define TC_UOPPRE  (TC_UOPPRE1 | TC_UOPPRE2)
+
 #define TC_BINOP   (TC_BINOPX | TC_COMMA | TC_PIPE | TC_IN)
 //#define       TC_UNARYOP (TC_UOPPRE | TC_UOPPOST)
 #define TC_OPERAND (TC_VARIABLE | TC_ARRAY | TC_FUNCTION \
                    | TC_BUILTIN | TC_LENGTH | TC_GETLINE \
                    | TC_SEQSTART | TC_STRING | TC_NUMBER)
+#define TC_LVALUE (TC_VARIABLE | TC_ARRAY)
 
 #define TC_STATEMNT (TC_STATX | TC_WHILE)
 #define TC_OPTERM  (TC_SEMICOL | TC_NEWLINE)
@@ -284,7 +323,6 @@ typedef struct tsplitter_s {
 #define OF_CHECKED  0x200000
 #define OF_REQUIRED 0x400000
 
-
 /* combined operator flags */
 #define xx      0
 #define xV      OF_RES2
@@ -313,10 +351,8 @@ typedef struct tsplitter_s {
 #define PRIMASK2  0x7E000000
 
 /* Operation classes */
-
 #define SHIFT_TIL_THIS  0x0600
 #define RECUR_FROM_THIS 0x1000
-
 enum {
         OC_DELETE = 0x0100,     OC_EXEC = 0x0200,       OC_NEWSOURCE = 0x0300,
         OC_PRINT = 0x0400,      OC_PRINTF = 0x0500,     OC_WALKINIT = 0x0600,
@@ -411,7 +447,9 @@ static const uint32_t tokeninfo[] ALIGN4 = {
         OC_REGEXP,
         xS|'a',                  xS|'w',                  xS|'|',
         OC_UNARY|xV|P(9)|'p',    OC_UNARY|xV|P(9)|'m',
-        OC_UNARY|xV|P(9)|'P',    OC_UNARY|xV|P(9)|'M',    OC_FIELD|xV|P(5),
+#define TI_PREINC (OC_UNARY|xV|P(9)|'P')
+#define TI_PREDEC (OC_UNARY|xV|P(9)|'M')
+        TI_PREINC,               TI_PREDEC,               OC_FIELD|xV|P(5),
         OC_COMPARE|VV|P(39)|5,   OC_MOVE|VV|P(74),        OC_REPLACE|NV|P(74)|'+', OC_REPLACE|NV|P(74)|'-',
         OC_REPLACE|NV|P(74)|'*', OC_REPLACE|NV|P(74)|'/', OC_REPLACE|NV|P(74)|'%', OC_REPLACE|NV|P(74)|'&',
         OC_BINARY|NV|P(29)|'+',  OC_BINARY|NV|P(29)|'-',  OC_REPLACE|NV|P(74)|'&', OC_BINARY|NV|P(15)|'&',
@@ -1070,6 +1108,10 @@ static uint32_t next_token(uint32_t expected)
         uint32_t tc;
         const uint32_t *ti;
 
+        debug_printf_parse("%s() expected(%x):", __func__, expected);
+        debug_parse_print_tc(expected);
+        debug_printf_parse("\n");
+
         if (t_rollback) {
                 debug_printf_parse("%s: using rolled-back token\n", __func__);
                 t_rollback = FALSE;
@@ -1226,7 +1268,9 @@ static uint32_t next_token(uint32_t expected)
                                 EMSG_UNEXP_EOS : EMSG_UNEXP_TOKEN);
         }
 
-        debug_printf_parse("%s: returning, ltclass:%x t_double:%f\n", __func__, ltclass, t_double);
+        debug_printf_parse("%s: returning, t_double:%f ltclass:", __func__, t_double);
+        debug_parse_print_tc(ltclass);
+        debug_printf_parse("\n");
         return ltclass;
 #undef concat_inserted
 #undef save_tclass
@@ -1266,7 +1310,7 @@ static node *condition(void)
 
 /* parse expression terminated by given argument, return ptr
  * to built subtree. Terminator is eaten by parse_expr */
-static node *parse_expr(uint32_t iexp)
+static node *parse_expr(uint32_t term_tc)
 {
         node sn;
         node *cn = &sn;
@@ -1274,13 +1318,15 @@ static node *parse_expr(uint32_t iexp)
         uint32_t tc, xtc;
         var *v;
 
-        debug_printf_parse("%s(%x)\n", __func__, iexp);
+        debug_printf_parse("%s() term_tc(%x):", __func__, term_tc);
+        debug_parse_print_tc(term_tc);
+        debug_printf_parse("\n");
 
         sn.info = PRIMASK;
         sn.r.n = sn.a.n = glptr = NULL;
-        xtc = TC_OPERAND | TC_UOPPRE | TC_REGEXP | iexp;
+        xtc = TC_OPERAND | TC_UOPPRE | TC_REGEXP | term_tc;
 
-        while (!((tc = next_token(xtc)) & iexp)) {
+        while (!((tc = next_token(xtc)) & term_tc)) {
 
                 if (glptr && (t_info == (OC_COMPARE | VV | P(39) | 2))) {
                         /* input redirection (<) attached to glptr node */
@@ -1313,25 +1359,28 @@ static node *parse_expr(uint32_t iexp)
                                         next_token(TC_GETLINE);
                                         /* give maximum priority to this pipe */
                                         cn->info &= ~PRIMASK;
-                                        xtc = TC_OPERAND | TC_UOPPRE | TC_BINOP | iexp;
+                                        xtc = TC_OPERAND | TC_UOPPRE | TC_BINOP | term_tc;
                                 }
                         } else {
                                 cn->r.n = vn;
-                                xtc = TC_OPERAND | TC_UOPPRE | TC_BINOP | iexp;
+                                xtc = TC_OPERAND | TC_UOPPRE | TC_BINOP | term_tc;
                         }
                         vn->a.n = cn;
 
                 } else {
-                        debug_printf_parse("%s: other\n", __func__);
+                        debug_printf_parse("%s: other, t_info:%x\n", __func__, t_info);
                         /* for operands and prefix-unary operators, attach them
                          * to last node */
                         vn = cn;
                         cn = vn->r.n = new_node(t_info);
                         cn->a.n = vn;
+
                         xtc = TC_OPERAND | TC_UOPPRE | TC_REGEXP;
+                        if (t_info == TI_PREINC || t_info == TI_PREDEC)
+                                xtc = TC_LVALUE | TC_UOPPRE1;
                         if (tc & (TC_OPERAND | TC_REGEXP)) {
                                 debug_printf_parse("%s: TC_OPERAND | TC_REGEXP\n", __func__);
-                                xtc = TC_UOPPRE | TC_UOPPOST | TC_BINOP | TC_OPERAND | iexp;
+                                xtc = TC_UOPPRE | TC_UOPPOST | TC_BINOP | TC_OPERAND | term_tc;
                                 /* one should be very careful with switch on tclass -
                                  * only simple tclasses should be used! */
                                 switch (tc) {
@@ -1388,7 +1437,7 @@ static node *parse_expr(uint32_t iexp)
                                 case TC_GETLINE:
                                         debug_printf_parse("%s: TC_GETLINE\n", __func__);
                                         glptr = cn;
-                                        xtc = TC_OPERAND | TC_UOPPRE | TC_BINOP | iexp;
+                                        xtc = TC_OPERAND | TC_UOPPRE | TC_BINOP | term_tc;
                                         break;
 
                                 case TC_BUILTIN:
@@ -1603,6 +1652,8 @@ static void parse_program(char *p)
         func *f;
         var *v;
 
+        debug_printf_parse("%s()\n", __func__);
+
         g_pos = p;
         t_lineno = 1;
         while ((tclass = next_token(TC_EOF | TC_OPSEQ | TC_GRPSTART |