evalexpr: initial recursive descent parser

Makefile

@@ -0,0 +1,23 @@
+CC = gcc
+CPPFLAGS = -Isrc/ -D_POSIX_C_SOURCE=200809L
+CFLAGS = -Wall -Wextra -pedantic -Werror -std=c99
+VPATH = src/
+
+SRC = \
+    src/ast/ast.c \
+    src/eval/eval.c \
+    src/parse/parse.c \
+
+BIN = evalexpr
+OBJ = $(SRC:.c=.o)
+
+.PHONY: all
+all: $(BIN)
+
+# Write this one rule instead of using the implicit rules to buid at the root
+$(BIN): $(OBJ) src/evalexpr.o
+
+.PHONY: clean
+clean:
+	$(RM) $(OBJ) # remove object files
+	$(RM) $(BIN) # remove main program