Create expression struct and memory pool

scripts/build.sh

@@ -2,12 +2,18 @@ cd "$(git rev-parse --show-toplevel)"
 
 CFLAGS="$CFLAGS -std=c11 -pedantic -Wall -Wextra"
 CFLAGS="$CFLAGS -Og -ggdb"
+CFLAGS="$CFLAGS -Ilib/include"
 
 mkdir -p build
 
+# Build library
+clang $CFLAGS -c -o build/memory_pool.o lib/memory_pool.c
+clang $CFLAGS -c -o build/reader.o lib/reader.c
+ar -crs build/lib.a build/memory_pool.o build/reader.o
+
 # Build tests
 clang $CFLAGS -Itests -c -o build/testing.o tests/testing.c
 
 # Build application
 clang $CFLAGS -c -o build/main.o app/main.c
-clang $CFLAGS -o build/infix-calculator build/main.o
+clang $CFLAGS -o build/infix-calculator build/main.o build/lib.a