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Diffstat (limited to '')
| -rw-r--r-- | bin/when.y | 353 |
1 files changed, 353 insertions, 0 deletions
diff --git a/bin/when.y b/bin/when.y new file mode 100644 index 00000000..46651ebb --- /dev/null +++ b/bin/when.y @@ -0,0 +1,353 @@ +/* Copyright (C) 2019, 2022 June McEnroe <june@causal.agency> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +%{ + +#include <ctype.h> +#include <err.h> +#include <errno.h> +#include <limits.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <strings.h> +#include <sysexits.h> +#include <time.h> + +static void yyerror(const char *str); +static int yylex(void); + +#define YYSTYPE struct tm + +static const char *Days[7] = { + "Sunday", "Monday", "Tuesday", "Wednesday", + "Thursday", "Friday", "Saturday", +}; + +static const char *Months[12] = { + "January", "February", "March", "April", "May", "June", + "July", "August", "September", "October", "November", "December", +}; + +static const struct tm Week = { .tm_mday = 7 }; + +static struct tm normalize(struct tm date) { + time_t time = timegm(&date); + struct tm *norm = gmtime(&time); + if (!norm) err(EX_OSERR, "gmtime"); + return *norm; +} + +static struct tm today(void) { + time_t now = time(NULL); + struct tm *local = localtime(&now); + if (!local) err(EX_OSERR, "localtime"); + struct tm date = { + .tm_year = local->tm_year, + .tm_mon = local->tm_mon, + .tm_mday = local->tm_mday, + }; + return normalize(date); +} + +static struct tm monthDay(int month, int day) { + struct tm date = today(); + date.tm_mon = month; + date.tm_mday = day; + return normalize(date); +} + +static struct tm monthDayYear(int month, int day, int year) { + struct tm date = today(); + date.tm_mon = month; + date.tm_mday = day; + date.tm_year = year - 1900; + return normalize(date); +} + +static struct tm weekDay(int day) { + struct tm date = today(); + date.tm_mday += day - date.tm_wday; + return normalize(date); +} + +static struct tm scalarAdd(struct tm a, struct tm b) { + a.tm_mday += b.tm_mday; + a.tm_mon += b.tm_mon; + a.tm_year += b.tm_year; + return a; +} + +static struct tm scalarSub(struct tm a, struct tm b) { + a.tm_mday -= b.tm_mday; + a.tm_mon -= b.tm_mon; + a.tm_year -= b.tm_year; + return a; +} + +static struct tm dateAdd(struct tm date, struct tm scalar) { + return normalize(scalarAdd(date, scalar)); +} + +static struct tm dateSub(struct tm date, struct tm scalar) { + return normalize(scalarSub(date, scalar)); +} + +static struct tm dateDiff(struct tm a, struct tm b) { + time_t atime = timegm(&a), btime = timegm(&b); + if (atime < btime) { + struct tm x = a; + a = b; + b = x; + time_t xtime = atime; + atime = btime; + btime = xtime; + } + struct tm diff = { + .tm_year = a.tm_year - b.tm_year, + .tm_mon = a.tm_mon - b.tm_mon, + .tm_mday = a.tm_mday - b.tm_mday, + }; + if ( + a.tm_mon < b.tm_mon || + (a.tm_mon == b.tm_mon && a.tm_mday < b.tm_mday) + ) { + diff.tm_year--; + diff.tm_mon += 12; + } + if (a.tm_mday < b.tm_mday) { + diff.tm_mon--; + diff.tm_mday = 0; + while (dateAdd(b, diff).tm_mday != a.tm_mday) diff.tm_mday++; + } + diff.tm_yday = (atime - btime) / 24 / 60 / 60; + return diff; +} + +static struct { + size_t cap, len; + struct tm *ptr; +} dates; + +static struct tm getDate(const char *name) { + for (size_t i = 0; i < dates.len; ++i) { + if (!strcmp(dates.ptr[i].tm_zone, name)) return dates.ptr[i]; + } + return (struct tm) {0}; +} + +static void setDate(const char *name, struct tm date) { + for (size_t i = 0; i < dates.len; ++i) { + if (strcmp(dates.ptr[i].tm_zone, name)) continue; + char *tm_zone = dates.ptr[i].tm_zone; + dates.ptr[i] = date; + dates.ptr[i].tm_zone = tm_zone; + return; + } + if (dates.len == dates.cap) { + dates.cap = (dates.cap ? dates.cap * 2 : 8); + dates.ptr = realloc(dates.ptr, sizeof(*dates.ptr) * dates.cap); + if (!dates.ptr) err(EX_OSERR, "realloc"); + } + dates.ptr[dates.len] = date; + dates.ptr[dates.len].tm_zone = strdup(name); + if (!dates.ptr[dates.len].tm_zone) err(EX_OSERR, "strdup"); + dates.len++; +} + +static bool silent; + +static void printDate(struct tm date) { + if (silent) return; + printf( + "%.3s %.3s %d %d\n", + Days[date.tm_wday], Months[date.tm_mon], + date.tm_mday, 1900 + date.tm_year + ); +} + +static void printScalar(struct tm scalar) { + if (silent) return; + if (scalar.tm_year) printf("%dy ", scalar.tm_year); + if (scalar.tm_mon) printf("%dm ", scalar.tm_mon); + if (scalar.tm_mday % 7) { + printf("%dd ", scalar.tm_mday); + } else if (scalar.tm_mday) { + printf("%dw ", scalar.tm_mday / 7); + } + if (scalar.tm_yday && scalar.tm_mon) { + if (scalar.tm_yday >= 7) { + printf("(%dw", scalar.tm_yday / 7); + if (scalar.tm_yday % 7) { + printf(" %dd", scalar.tm_yday % 7); + } + printf(") "); + } + printf("(%dd) ", scalar.tm_yday); + } + printf("\n"); +} + +%} + +%token Name Number Month Day +%left '+' '-' +%right '=' '<' '>' + +%% + +expr: + date { printDate($1); } + | scalar { printScalar($1); } + ; + +date: + dateLit + | Name { $$ = getDate($1.tm_zone); free($1.tm_zone); } + | Name '=' date { setDate($1.tm_zone, $3); free($1.tm_zone); $$ = $3; } + | '(' date ')' { $$ = $2; } + | '<' date { $$ = dateSub($2, Week); } + | '>' date { $$ = dateAdd($2, Week); } + | date '+' scalar { $$ = dateAdd($1, $3); } + | date '-' scalar { $$ = dateSub($1, $3); } + ; + +scalar: + scalarLit + | '(' scalar ')' { $$ = $2; } + | scalar '+' scalar { $$ = scalarAdd($1, $3); } + | scalar '-' scalar { $$ = scalarSub($1, $3); } + | date '-' date { $$ = dateDiff($1, $3); } + ; + +dateLit: + { $$ = today(); } + | '.' { $$ = today(); } + | Month Number { $$ = monthDay($1.tm_mon, $2.tm_sec); } + | Month Number Number { $$ = monthDayYear($1.tm_mon, $2.tm_sec, $3.tm_sec); } + | Day { $$ = weekDay($1.tm_wday); } + ; + +scalarLit: + Number 'd' { $$ = (struct tm) { .tm_mday = $1.tm_sec }; } + | Number 'w' { $$ = (struct tm) { .tm_mday = 7 * $1.tm_sec }; } + | Number 'm' { $$ = (struct tm) { .tm_mon = $1.tm_sec }; } + | Number 'y' { $$ = (struct tm) { .tm_year = $1.tm_sec }; } + ; + +%% + +static void yyerror(const char *str) { + warnx("%s", str); +} + +static const char *input; + +static int yylex(void) { + while (isspace(*input)) input++; + if (!*input) return EOF; + + if (isdigit(*input)) { + char *rest; + yylval.tm_sec = strtol(input, &rest, 10); + input = rest; + return Number; + } + + size_t len; + for (len = 0; isalnum(input[len]) || input[len] == '_'; ++len); + + if (len >= 3) { + for (int i = 0; i < 7; ++i) { + if (strncasecmp(input, Days[i], len)) continue; + yylval.tm_wday = i; + input += len; + return Day; + } + + for (int i = 0; i < 12; ++i) { + if (strncasecmp(input, Months[i], len)) continue; + yylval.tm_mon = i; + input += len; + return Month; + } + } + + if (len && (len != 1 || !strchr("dwmy", *input))) { + yylval.tm_zone = strndup(input, len); + if (!yylval.tm_zone) err(EX_OSERR, "strndup"); + input += len; + return Name; + } + + return *input++; +} + +int main(int argc, char *argv[]) { + size_t cap = 0; + char *line = NULL; + + char path[PATH_MAX]; + const char *configHome = getenv("XDG_CONFIG_HOME"); + if (configHome) { + snprintf(path, sizeof(path), "%s/when/dates", configHome); + } else { + snprintf(path, sizeof(path), "%s/.config/when/dates", getenv("HOME")); + } + + FILE *file = fopen(path, "r"); + if (file) { + silent = true; + while (0 < getline(&line, &cap, file)) { + input = line; + yyparse(); + } + fclose(file); + silent = false; + } else if (errno != ENOENT) { + err(EX_CONFIG, "%s", path); + } + + if (argc > 1) { + if (strcmp(argv[1], "-")) { + input = argv[1]; + return yyparse(); + } else { + for (size_t i = 0; i < dates.len; ++i) { + printf("%s: ", dates.ptr[i].tm_zone); + printScalar(dateDiff(today(), dates.ptr[i])); + } + return EX_OK; + } + } + + struct tm date = today(); + printDate(date); + printf("\n"); + + while (0 < getline(&line, &cap, stdin)) { + if (line[0] == '\n') continue; + + if (today().tm_mday != date.tm_mday) { + warnx("the date has changed"); + date = today(); + } + + input = line; + yyparse(); + printf("\n"); + } +} |