crepl

commit 3b01d7d6fc61e75421d6133e505b709f7c605c58
parent 0615e712b31c255559e50c64329c4ba1acacf1b1
Author: Demonstrandum <moi@knutsen.co>
Date:   Tue, 23 Jun 2020 11:24:26 +0100

Save and manage history.

Diffstat:
M
Makefile
 | 
30
+++++++++++++++++++++---------
M
README.md
 | 
28
++++++++++++++++++++++++++++
M
src/main.c
 | 
52
++++++++++++++++++++++++++++++++++++++++++----------
M
src/prelude.c
 | 
11
++++++-----

4 files changed, 97 insertions(+), 24 deletions(-)
diff --git a/Makefile b/Makefile
@@ -1,19 +1,31 @@
-CC=gcc
-CFLAGS=-Wall -Wpedantic
-TARGET=crepl
-OBJS=main.o prelude.o parse.o displays.o error.o execute.o
-LINKS=-lm -lreadline
+CC := gcc
+CFLAGS := -Wall -Wpedantic
+TARGET := crepl
+OBJS := main.o prelude.o parse.o displays.o error.o execute.o
+LINKS := -lm -lreadline
 
-all: clean $(OBJS)
+ifeq ($(PREFIX),)
+    PREFIX := /usr/local
+endif
+
+all: clean $(TARGET)
+	@printf "\033[1mBuilt \`$(TARGET)' successfully.\033[0m\n"
+
+$(TARGET): $(OBJS)
 	$(CC) -o $(TARGET) $(LINKS) $(OBJS)
-	@printf "\n\033[1mBuilt \`$(TARGET)' successfully.\033[0m\n"
 
-prelude.o: error.o
-	$(CC) -c $(CFLAGS) src/prelude.c
+install: $(TARGET)
+	@echo "Installing to $(PREFIX)/bin/$(TARGET)."
+	install -d $(PREFIX)/bin
+	install -m 755 $(TARGET) $(PREFIX)/bin
 
 main.o: prelude.o parse.o error.o
 	$(CC) -c $(CFLAGS) src/main.c
 
+prelude.o: error.o
+	$(CC) -c $(CFLAGS) src/prelude.c
+
+
 parse.o: error.o
 	$(CC) -c $(CFLAGS) src/parse.c
 
diff --git a/README.md b/README.md
@@ -0,0 +1,28 @@
+# CREPL
+> **C**alculator **REPL**
+
+A command line calculator read-eval-print-loop,
+with intuitive mathematical notation as syntax.
+
+## Install
+
+You'll need `git` (if cloning), a C compiler (e.g. `gcc`)
+and `make` (`build-essential` / `base-devel`).
+
+### Clone
+Clone / Download this repositroy however you like, e.g.
+```console
+git clone "https://github.com/Demonstrandum/crepl.git"
+```
+
+Then change directory into it:
+```console
+cd crepl
+```
+
+### Build & Install
+```console
+make  # Builds and compiles the project.
+sudo make install  # Installs the program system wide.
+```
+
diff --git a/src/main.c b/src/main.c
@@ -1,9 +1,11 @@
 #include <stdio.h>
-#include <readline/readline.h>
-#include <readline/history.h>
-
 #include <stdlib.h>
 #include <string.h>
+#include <signal.h>
+#include <sys/stat.h>
+
+#include <readline/readline.h>
+#include <readline/history.h>
 
 #include "prelude.h"
 #include "error.h"
@@ -12,25 +14,54 @@
 
 static const char *PROMPT = "::> ";
 
+void sigint_handle(int _)
+{
+	printf("\b\b  ");  // Obsucre '^C' output.
+	printf("\nInterrupted, [Ctrl-D] to stop inputting.\n");
+    rl_on_new_line();
+	rl_replace_line("", 0);
+    rl_redisplay();
+}
+
 int main(int argc, char **argv)
 {
+	// Welcome messsage.
 	printf("\033[1m");
 	printf("CREPL — Calculator Read Eval Print Loop");
 	printf("\033[0m");
 	puts(" (" COMPILER ") (" __DATE__ ")");
-	puts("Type \"exit\" or [Ctrl+D] (i.e. EOF) to quit.");
+	puts("Type \"exit\" or [Ctrl-D] (i.e. EOF) to quit.");
+
+	// Configure readline.
+	rl_clear_signals();
+	rl_bind_key('\t', rl_insert);
+	signal(SIGINT, sigint_handle);
+
+	// Create or fetch history file.
+	char cache_loc[128] = "~/.cache/";
+	char *tmp = NULL;
 
-	rl_bind_key('\t', rl_complete);
+	if ((tmp = getenv("XDG_CACHE_HOME")) != NULL)
+		strcpy(cache_loc, tmp);
+	else if ((tmp = getenv("HOME")) != NULL)
+		sprintf(cache_loc, "%s/.cache/", tmp);
+
+	mkdir(cache_loc, 0777);
+	strcat(cache_loc, "/crepl.history");
+	read_history(cache_loc);
 
 	char *response = NULL;
 	do {
-		response = readline(PROMPT);
-		add_history(response);
+		char *line = readline(PROMPT);
 
-		if (response == NULL
-		|| strcmp("exit", downcase(trim(response))) == 0)
+		if (line == NULL
+		|| strcmp("exit", downcase(trim(line))) == 0)
 			break;
 
+		if (response == NULL || strcmp(line, response) != 0)
+			add_history(line);
+		response = line;
+
 		// Try to lex & parse the input.
 		ParseNode *tree = parse(response);
 
@@ -46,9 +77,10 @@ int main(int argc, char **argv)
 		printf("#=> %s\n", response);
 
 		free_parsenode(tree);
-		free(response);
 	} while (true);
 
+	write_history(cache_loc);
+
 	printf("\r\033[2K");
 	printf("Buh-bye.\n");
 
diff --git a/src/prelude.c b/src/prelude.c
@@ -2,15 +2,16 @@
 
 char *trim(char *str)
 {
-	while (isspace(*str))
-        ++str;
+	char *p = strdup(str);
+	while (isspace(*p))
+        ++p;
 
-	char *end = str + strlen(str) - 1;
-    while (end > str && isspace(*end))
+	char *end = p + strlen(p) - 1;
+    while (end > p && isspace(*end))
         --end;
 
     *(end + 1) = '\0';
-    return str;
+    return p;
 }