The economic concept of guns or butter means that
a. a person can spend money on either sports equipment or food.
b. a company must decide whether to manufacture guns or butter.
c. a government must decide to produce more or less military or consumer goods.
d. a government can buy unlimited military and civilian goods if it is rich enough.

Assemblies do not have written codes of laws. laws are matters for magistrates and courts, not assemblies. codes of law are things such as civil law, criminal law, and constitutional law. what assemblies have are procedures regarding debating, voting and other business they might carry out.  also note that rome had three assemblies: the assembly of the soldiers, the assembly of the tribes, and the plebeian councils.