From 4c80a78661bdd2efe2f0a07b496f2a6cc6005a06 Mon Sep 17 00:00:00 2001
From: Trent Huber <trentmhuber@gmail.com>
Date: Tue, 1 Jul 2025 01:12:24 -0400
Subject: [PATCH] File redirection tokenization

---
 src/input.c |  3 ++-
 src/lex.c   | 70 +++++++++++++++++++++++++++++++++++++++++++++--------
 src/lex.h   | 39 ++++++++++++++++++++++++-----
 src/main.c  |  1 +
 4 files changed, 96 insertions(+), 17 deletions(-)

diff --git a/src/input.c b/src/input.c
index 96b0f79..29dc7b1 100644
--- a/src/input.c
+++ b/src/input.c
@@ -120,10 +120,11 @@ reset:
 	fpurge(stdout);
 	push(&history, start);
 
+	*buffer = ';';
 	*end = ';';
 	*++end = '\0';
 
 	signal(SIGCHLD, SIG_DFL);
 
-	return start;
+	return buffer;
 }
diff --git a/src/lex.c b/src/lex.c
index 2843d65..642e2c8 100644
--- a/src/lex.c
+++ b/src/lex.c
@@ -1,15 +1,39 @@
 #include <fcntl.h>
 #include <stddef.h>
 #include <stdlib.h>
+#include <err.h>
+#include <stdio.h> // DEBUG
 
 #include "history.h"
 #include "lex.h"
 
-static char *tokens[BUFLEN + 1];
-static struct cmd cmds[1 + (BUFLEN + 1) / 2 + 1] = {{.type = SEMI}};
+static char *tokens[1 + BUFLEN + 1];
+static struct cmd cmds[1 + (BUFLEN + 1) / 2 + 1] = {{.args = tokens, .f = cmds->freds}};
+
+void printfreds(struct cmd *c) {
+	for (; c->f->mode != END; ++c->f) {
+		printf("%d", c->f->newfd);
+		switch (c->f->mode) {
+		case READ:
+			fputs("<", stdout);
+			break;
+		case WRITE:
+			fputs(">", stdout);
+			break;
+		case READWRITE:
+			fputs("<>", stdout);
+			break;
+		case APPEND:
+			fputs(">>", stdout);
+			break;
+		default:;
+		}
+		puts(c->f->old.name);
+	}
+}
 
 struct cmd *lex(char *b) {
-	char **t;
+	char **t, *end;
 	struct cmd *c;
 	
 	if (!b) return NULL;
@@ -17,34 +41,60 @@ struct cmd *lex(char *b) {
 	c = cmds;
 	while (*b) switch (*b) {
 	default:
-		if (!*(b - 1)) {
-			if (c->type) {
-				(++c)->args = t;
-				c->type = NONE;
-			}
+		if (!*(b - 1)) { // Start of a token
+			if (!c->args) c->args = t; // Start of a command
 			*t++ = b;
 		}
 		++b;
 		break;
 	case '<':
 	case '>':
+		if (*(b - 1)) {
+			if ((c->f->newfd = strtol(*--t, &end, 10)) < 0 || end != b) {
+				warnx("Invalid file redirection operator");
+				c->args = NULL;
+				return c - 1;
+			}
+			if (c->args == t) c->args = NULL;
+		} else c->f->newfd = *b == '>';
+		c->f->mode = *b++;
+		if (*b == '>') {
+			++b;
+			++c->f->mode;
+		}
+		c->f++->old.name = b;
+		if (*b == '&') ++b;
 		break;
 	case '&':
 	case '|':
 		if (*b == *(b + 1)) *b = '\0';
 	case ';':
-		if (c->type == NONE) {
+		if (c->args) {
 			*t++ = NULL;
 			if (!*b) {
 				++b;
 				++c->type;
 			}
 			c->type += *b;
+			*(c->f) = (struct fred){0};
+			c->f = c->freds;
+
+			(++c)->args = NULL;
 		}
+		c->f = c->freds;
 	case ' ':
 		*b++ = '\0';
 	}
-	*++c = (struct cmd){0};
+	switch (c->type) {
+	case AND:
+	case PIPE:
+	case OR:
+		warnx("Command left open-ended");
+		c->args = NULL;
+		return c - 1;
+	default:
+		*++c = (struct cmd){0};
+	}
 
 	return cmds;
 }
diff --git a/src/lex.h b/src/lex.h
index b865490..f3b26fb 100644
--- a/src/lex.h
+++ b/src/lex.h
@@ -1,5 +1,4 @@
 enum terminator {
-	NONE,
 	SEMI = ';',
 	BG = '&',
 	AND,
@@ -7,21 +6,49 @@ enum terminator {
 	OR,
 };
 
+enum mode {
+	END,
+	READ = '<',
+	READWRITE,
+	WRITE = '>',
+	APPEND,
+};
+
+enum type {
+	FD,
+	NAME,
+};
+
+// if (cmd->f->type == NAME) cmd->f->old.fd = open(cmd->f->old.name, mode);
+// dup2(cmd->f->newfd, cmd->f->old.fd);
+// if (cmd->f->type == NAME) close(cmd->f->old.fd);
+// 
+// // vs.
+// 
+// if (*cmd->f->oldfd == '&') fd = open(++cmd->f->oldfd, mode);
+// dup2(cmd->f->newfd, cmd->
+
 struct fred {
-	int newfd, mode;
-	char *oldfd;
+	int newfd;
+	enum mode mode;
+	enum type type;
+	union {
+		int fd;
+		char *name;
+	} old;
 };
 
-/* a>&b -> dup2(b, a); reopen(a, "w");
- * a<&b -> dup2(b, a); reopen(a, "r");
+/* a>&b -> dup2(b, a); reopen(a, "w"); | (1)>&3 -> dup2(3, 1);
+ * a<&b -> dup2(b, a); reopen(a, "r"); | (0)<&3 -> dup2(3, 0);
  * x >a >b >c ...
  */
 
 struct cmd {
 	char **args;
 	enum terminator type;
+	struct fred *f, freds[(BUFLEN - 1) / 3 + 1];
 	int pipe[2];
-	struct fred freds[(BUFLEN - 1) / 3 + 1];
 };
 
+void printfreds(struct cmd *c);
 struct cmd *lex(char *b);
diff --git a/src/main.c b/src/main.c
index 2b00fe5..d090458 100644
--- a/src/main.c
+++ b/src/main.c
@@ -44,6 +44,7 @@ int main(void) {
 
 	while ((cmd = lex(input()))) {
 		while (prev = cmd++, cmd->args) {
+			printfreds(cmd);
 			ispipe = cmd->type == PIPE || prev->type == PIPE;
 			ispipestart = ispipe && prev->type != PIPE;
 			ispipeend = ispipe && cmd->type != PIPE;
-- 
2.51.0