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awk: improve comments and constants, no code changes 

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
master
Denys Vlasenko 2024-07-10 06:58:51 +02:00
parent 45d471d435
commit 2eea3494f1
1 changed files with 27 additions and 20 deletions
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47
editors/awk.c
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@ -307,13 +307,13 @@ static void debug_parse_print_tc(uint32_t n)
| TC_LENGTH)
#define TS_CONCAT_R (TS_OPERAND | TS_UOPPRE)
#define OF_RES1 0x010000
#define OF_RES2 0x020000
#define OF_STR1 0x040000
#define OF_STR2 0x080000
#define OF_NUM1 0x100000
#define OF_CHECKED 0x200000
#define OF_REQUIRED 0x400000
#define OF_RES1 0x010000 /* evaluate(left_node) */
#define OF_RES2 0x020000 /* evaluate(right_node) */
#define OF_STR1 0x040000 /* ...and use its string value */
#define OF_STR2 0x080000 /* ...and use its string value */
#define OF_NUM1 0x100000 /* ...and use its numeric value */
#define OF_REQUIRED 0x200000 /* left_node must not be NULL */
#define OF_CHECKED 0x400000 /* range pattern flip-flop bit */
/* combined operator flags */
#define xx 0
@ -331,17 +331,18 @@ static void debug_parse_print_tc(uint32_t n)
#define OPCLSMASK 0xFF00
#define OPNMASK 0x007F
/* operator priority is a highest byte (even: r->l, odd: l->r grouping)
* (for builtins it has different meaning)
/* operator precedence is the highest byte (even: r->l, odd: l->r grouping)
* (for builtins the byte has a different meaning)
*/
#undef P
#undef PRIMASK
#undef PRIMASK2
#define PRIMASK 0x7F000000
#define PRIMASK2 0x7E000000
/* Smaller 'x' means _higher_ operator precedence */
#define PRECEDENCE(x) (x << 24)
#define P(x) PRECEDENCE(x)
#define PRIMASK 0x7F000000
#define PRIMASK2 0x7E000000
#define LOWEST_PRECEDENCE PRIMASK
/* Operation classes */
#define SHIFT_TIL_THIS 0x0600
@ -1424,7 +1425,7 @@ static node *parse_expr(uint32_t term_tc)
debug_parse_print_tc(term_tc);
debug_printf_parse("\n");
sn.info = PRIMASK;
sn.info = LOWEST_PRECEDENCE;
sn.r.n = sn.a.n = getline_node = NULL;
expected_tc = TS_OPERAND | TS_UOPPRE | TC_REGEXP | term_tc;
@ -1443,7 +1444,7 @@ static node *parse_expr(uint32_t term_tc)
if (tc & (TS_BINOP | TC_UOPPOST)) {
debug_printf_parse("%s: TS_BINOP | TC_UOPPOST tc:%x\n", __func__, tc);
/* for binary and postfix-unary operators, jump back over
* previous operators with higher priority */
* previous operators with higher precedence */
vn = cn;
while (((t_info & PRIMASK) > (vn->a.n->info & PRIMASK2))
|| (t_info == vn->info && t_info == TI_COLON)
@ -1451,7 +1452,7 @@ static node *parse_expr(uint32_t term_tc)
vn = vn->a.n;
if (!vn->a.n) syntax_error(EMSG_UNEXP_TOKEN);
}
if (t_info == TI_TERNARY) /* "?" operator */
if (t_info == TI_TERNARY) /* "?" token */
//TODO: why?
t_info += PRECEDENCE(6);
cn = vn->a.n->r.n = new_node(t_info);
@ -1483,11 +1484,10 @@ static node *parse_expr(uint32_t term_tc)
}
expected_tc = TS_OPERAND | TS_UOPPRE | TC_REGEXP;
if (t_info == TI_PGETLINE) {
/* it's a pipe token "|" */
next_token(TC_GETLINE);
/* give maximum priority to this pipe */
cn->info &= ~PRIMASK;
if (t_info == TI_PGETLINE) { /* "|" token */
next_token(TC_GETLINE); /* must be folowed by "getline" */
/* give maximum precedence to this pipe */
cn->info &= ~PRIMASK; /* sets PRECEDENCE(0) */
expected_tc = TS_OPERAND | TS_UOPPRE | TS_BINOP | term_tc;
}
} else {
@ -1498,7 +1498,7 @@ static node *parse_expr(uint32_t term_tc)
vn->a.n = cn;
continue;
}
/* It wasn't a binary or unary_postfix operator */
/* It wasn't a binary or postfix-unary operator */
debug_printf_parse("%s: other, t_info:%x\n", __func__, t_info);
/* for operands and prefix-unary operators, attach them
@ -1572,6 +1572,13 @@ static node *parse_expr(uint32_t term_tc)
break;
case TC_GETLINE:
/* "getline" is a function, not a statement.
* Works in gawk:
* r = ["SHELL CMD" | ] getline [VAR] [<"FILE"]
* if (getline <"FILE" < 0) print "Can't read FILE"
* while ("SHELL CMD" | getline > 0) ...
* Returns: 1 successful read, 0 EOF, -1 error (sets ERRNO)
*/
debug_printf_parse("%s: TC_GETLINE\n", __func__);
getline_node = cn;
expected_tc = TS_OPERAND | TS_UOPPRE | TS_BINOP | term_tc;