Data commit

Task/S-expressions/C/s-expressions-1.c

@@ -0,0 +1,226 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+
+enum { S_NONE, S_LIST, S_STRING, S_SYMBOL };
+
+typedef struct {
+	int type;
+	size_t len;
+	void *buf;
+} s_expr, *expr;
+
+void whine(const char *s)
+{
+	fprintf(stderr, "parse error before ==>%.10s\n", s);
+}
+
+expr parse_string(const char *s, char **e)
+{
+	expr ex = calloc(sizeof(s_expr), 1);
+	char buf[256] = {0};
+	int i = 0;
+
+	while (*s) {
+		if (i >= 256) {
+			fprintf(stderr, "string too long:\n");
+			whine(s);
+			goto fail;
+		}
+		switch (*s) {
+		case '\\':
+			switch (*++s) {
+			case '\\':
+			case '"':	buf[i++] = *s++;
+					continue;
+
+			default:	whine(s);
+					goto fail;
+			}
+		case '"':	goto success;
+		default:	buf[i++] = *s++;
+		}
+	}
+fail:
+	free(ex);
+	return 0;
+
+success:
+	*(const char **)e = s + 1;
+	ex->type = S_STRING;
+	ex->buf = strdup(buf);
+	ex->len = strlen(buf);
+	return ex;
+}
+
+expr parse_symbol(const char *s, char **e)
+{
+	expr ex = calloc(sizeof(s_expr), 1);
+	char buf[256] = {0};
+	int i = 0;
+
+	while (*s) {
+		if (i >= 256) {
+			fprintf(stderr, "symbol too long:\n");
+			whine(s);
+			goto fail;
+		}
+		if (isspace(*s)) goto success;
+		if (*s == ')' || *s == '(') {
+			s--;
+			goto success;
+		}
+
+		switch (*s) {
+		case '\\':
+			switch (*++s) {
+			case '\\': case '"': case '(': case ')':
+					buf[i++] = *s++;
+					continue;
+			default:	whine(s);
+					goto fail;
+			}
+		case '"':	whine(s);
+				goto success;
+		default:	buf[i++] = *s++;
+		}
+	}
+fail:
+	free(ex);
+	return 0;
+
+success:
+	*(const char **)e = s + 1;
+	ex->type = S_SYMBOL;
+	ex->buf = strdup(buf);
+	ex->len = strlen(buf);
+	return ex;
+}
+
+void append(expr list, expr ele)
+{
+	list->buf = realloc(list->buf, sizeof(expr) * ++list->len);
+	((expr*)(list->buf))[list->len - 1] = ele;
+}
+
+expr parse_list(const char *s, char **e)
+{
+	expr ex = calloc(sizeof(s_expr), 1), chld;
+	char *next;
+
+	ex->len = 0;
+
+	while (*s) {
+		if (isspace(*s)) {
+			s++;
+			continue;
+		}
+
+		switch (*s) {
+		case '"':
+			chld = parse_string(s+1, &next);
+			if (!chld) goto fail;
+			append(ex, chld);
+			s = next;
+			continue;
+		case '(':
+			chld = parse_list(s+1, &next);
+			if (!chld) goto fail;
+			append(ex, chld);
+			s = next;
+			continue;
+		case ')':
+			goto success;
+
+		default:
+			chld = parse_symbol(s, &next);
+			if (!chld) goto fail;
+			append(ex, chld);
+			s = next;
+			continue;
+		}
+	}
+
+fail:
+	whine(s);
+	free(ex);
+	return 0;
+
+success:
+	*(const char **)e = s+1;
+	ex->type = S_LIST;
+	return ex;
+}
+
+expr parse_term(const char *s, char **e)
+{
+	while (*s) {
+		if (isspace(*s)) {
+			s++;
+			continue;
+		}
+		switch(*s) {
+		case '(':
+			return parse_list(s+1, e);
+		case '"':
+			return parse_string(s+1, e);
+		default:
+			return parse_symbol(s+1, e);
+		}
+	}
+	return 0;
+}
+
+void print_expr(expr e, int depth)
+{
+#define sep() for(i = 0; i < depth; i++) printf("    ")
+	int i;
+	if (!e) return;
+
+
+	switch(e->type) {
+	case S_LIST:
+		sep();
+		puts("(");
+		for (i = 0; i < e->len; i++)
+			print_expr(((expr*)e->buf)[i], depth + 1);
+		sep();
+		puts(")");
+		return;
+	case S_SYMBOL:
+	case S_STRING:
+		sep();
+		if (e->type == S_STRING) putchar('"');
+		for (i = 0; i < e->len; i++) {
+			switch(((char*)e->buf)[i]) {
+			case '"':
+			case '\\':
+				putchar('\\');
+				break;
+			case ')': case '(':
+				if (e->type == S_SYMBOL)
+					putchar('\\');
+			}
+
+			putchar(((char*)e->buf)[i]);
+		}
+		if (e->type == S_STRING) putchar('"');
+		putchar('\n');
+		return;
+	}
+}
+
+int main()
+{
+	char *next;
+	const char *in = "((data da\\(\\)ta \"quot\\\\ed data\" 123 4.5)\n"
+			" (\"data\" (!@# (4.5) \"(mo\\\"re\" \"data)\")))";
+
+	expr x = parse_term(in, &next);
+
+	printf("input is:\n%s\n", in);
+	printf("parsed as:\n");
+	print_expr(x, 0);
+	return 0;
+}

Task/S-expressions/C/s-expressions-2.c

@@ -0,0 +1,24 @@
+input is:
+((data da\(\)ta "quot\\ed data" 123 4.5)
+ ("data" (!@# (4.5) "(mo\"re" "data)")))
+parsed as:
+(
+    (
+        data
+        da\(\)ta
+        "quot\\ed data"
+        123
+        4.5
+    )
+    (
+        "data"
+        (
+            !@#
+            (
+                4.5
+            )
+            "(mo\"re"
+            "data)"
+        )
+    )
+)