Chapter 30: Text Formatting and Diagnosticslinear-chapter30

Co-authored-by: Hsiang-Ying Fu <66062782+fuhsnn@users.noreply.github.com>
Co-authored-by: fuhsnn <66062782+fuhsnn@users.noreply.github.com>
Co-authored-by: Symious <14933944+symious@users.noreply.github.com>
Co-authored-by: Jun Kawasaki <jun784@gmail.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 86 insertions, 38 deletions

diff --git a/src/main/c/simple_crt.c b/src/main/c/simple_crt.c
index 8656a3cc..438ae5f9 100644
--- a/src/main/c/simple_crt.c
+++ b/src/main/c/simple_crt.c
@@ -1,58 +1,106 @@
 #include <stdint.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <termios.h>
+#include <unistd.h>
 
 // errno may be thread-local or a macro calling a platform accessor.
 int32_t simple_errno(void) { return errno; }
+int32_t simple_set_errno(int32_t error) { errno = error; return -1; }
+// Export platform errno constants; the buffering and retry loops are Simple.
+// C identifiers avoid the macros; linker names match the Simple bindings.
+int32_t simple_EINTR __asm__("EINTR") = EINTR;
+int32_t simple_EIO __asm__("EIO") = EIO;
+int32_t simple_EINVAL __asm__("EINVAL") = EINVAL;
+int32_t simple_EOVERFLOW __asm__("EOVERFLOW") = EOVERFLOW;
 
-// Native process arguments converted to ordinary Simple array layouts.
-// The outer array is mutable; every contained byte array is published as
-// immutable and non-null to Simple code.
+// Read one stdin byte, without terminal line editing or echo. POSIX terminals
+// include Cygwin consoles; redirected files/pipes need no mode change.
+// Return 0..255, or -1 with errno set to EOF or an OS error. Control characters,
+// including Ctrl-C, are returned as bytes so the mode is restored first.
+int32_t simple_getch(void) {
+    struct termios saved, mode;
+    int terminal = tcgetattr(STDIN_FILENO, &saved) == 0;
+    if (!terminal && errno != ENOTTY)
+        return -1;
+    if (terminal) {
+        mode = saved;
+        mode.c_lflag &= ~(ICANON | ECHO | ECHONL | ISIG | IEXTEN);
+        mode.c_iflag &= ~IXON;
+        mode.c_cc[VMIN] = 1;
+        mode.c_cc[VTIME] = 0;
+        if (tcsetattr(STDIN_FILENO, TCSANOW, &mode) != 0)
+            return -1;
+    }
+    unsigned char byte;
+    ssize_t count = read(STDIN_FILENO, &byte, 1);
+    int read_errno = errno;
+    if (terminal) {
+        int restored;
+        do {
+            restored = tcsetattr(STDIN_FILENO, TCSANOW, &saved);
+        } while (restored != 0 && errno == EINTR);
+        if (restored != 0)
+            return -1;
+    }
+    if (count < 0) {
+        errno = read_errno;
+        return -1;
+    }
+    if (count == 0) {
+        errno = EOF;
+        return -1;
+    }
+    return byte;
+}
+
+// Simple byte-array layout, used only by the floating-point formatter.
 typedef struct SimpleBytes {
     uint32_t len;
     unsigned char bytes[];
 } SimpleBytes;
 
-typedef struct SimpleArgs {
-    uint32_t len;
-    uint32_t pad;
-    SimpleBytes *args[];
-} SimpleArgs;
+// Binary floating-point conversion is the only native formatting primitive.
+// Buffering, integer conversion, string precision and padding live in sys.text.
+SimpleBytes *simple_text_float(double value, int64_t spec,
+                               int64_t width, int64_t precision) {
+    char kind = spec & 255;
+    if (!kind) { kind = 'g'; precision = 17; }
+    if (!strchr("fFeEgGaA", kind) || (spec & ~8191LL) ||
+        width < 0 || width > INT32_MAX || precision < -1 || precision > INT32_MAX)
+        abort();
+    char fmt[64], *p = fmt;
+    *p++ = '%';
+    const char *flags = "-+ #0";
+    for (int i=0; i<5; i++) if (spec & (256LL<<i)) *p++ = flags[i];
+    if (width) p += sprintf(p, "%d", (int)width);
+    if (precision >= 0) p += sprintf(p, ".%d", (int)precision);
+    *p++ = kind;
+    *p = 0;
+    int len = snprintf(NULL, 0, fmt, value);
+    if (len < 0) abort();
+    SimpleBytes *str = malloc(sizeof(*str) + (size_t)len + 1);
+    if (!str) abort();
+    str->len = (uint32_t)len;
+    snprintf((char *)str->bytes, (size_t)len + 1, fmt, value);
+    return str;
+}
+// Simple does not yet dereference raw native pointers. Keep just the argv
+// element access here; allocation and array construction live in sys/rt/simple_args.smp.
+const char *simple_argv(char **argv, int64_t index) {
+    return argv[index];
+}
 
 __attribute__((CALL_CONV))
-extern int64_t simple_main(SimpleArgs *args);
-
-static SimpleArgs *simple_args(int argc, char **argv) {
-    if (argc < 0 || (uint64_t)argc > UINT32_MAX)
-        return NULL;
-
-    SimpleArgs *args = calloc(1, sizeof(*args) + (size_t)argc * sizeof(args->args[0]));
-    if (args == NULL)
-        return NULL;
-    args->len = (uint32_t)argc;
-
-    for (int i = 0; i < argc; i++) {
-        size_t len = strlen(argv[i]);
-        if (len > UINT32_MAX) {
-            free(args);
-            return NULL;
-        }
-        SimpleBytes *str = malloc(sizeof(*str) + len);
-        if (str == NULL) {
-            for (int j = 0; j < i; j++) free(args->args[j]);
-            free(args);
-            return NULL;
-        }
-        str->len = (uint32_t)len;
-        memcpy(str->bytes, argv[i], len);
-        args->args[i] = str;
-    }
-    return args;
-}
+extern void *simple_args(int64_t argc, char **argv);
+__attribute__((CALL_CONV))
+extern int64_t simple_main(void *args);
 
 int main(int argc, char **argv) {
-    SimpleArgs *args = simple_args(argc, argv);
+    // simple_args fills every slot before publishing this as u8[~][].
+    void *args = simple_args(argc, argv);
     if (args == NULL)
         return 1;
     // The language-level hidden receiver is not part of the emitted ABI for