2eea3494f
Denys Vlasenko
2024-07-10
Subject
awk: improve comments and constants, no code changes
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editors/awk.c+27 -20
| @@ -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; | |