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@@ -0,0 +1,89 @@
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+RSpec.describe AST::FunctionCall do
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+ it 'evaluates built-in functions' do
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+ expect {
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+ AST::FunctionCall.new(
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+ AST::Identifier.new('print'),
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+ [AST::String.new('hello world')]
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+ ).execute(Environment.new)
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+ }.to output("hello world\n").to_stdout
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+ end
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+
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+ it 'evaluates user-defined functions' do
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+ env = Environment.new
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+ AST::FunctionDefinition.new(
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+ AST::Identifier.new('add_one'),
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+ [AST::Identifier.new('n')],
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+ AST::Block.new([
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+ AST::Binary.new(
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+ AST::Operators::ADD,
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+ AST::Identifier.new('n'),
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+ AST::Number.new(1.0)
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+ )
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+ ])
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+ ).execute(env)
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+ expect(
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+ AST::FunctionCall.new(
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+ AST::Identifier.new('add_one'),
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+ [AST::Number.new(5.0)]
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+ ).execute(env)
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+ ).to eq(6.0)
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+ end
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+
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+ # This corresponds to the program
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+ # function factorial(n) {
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+ # if n == 0 {
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+ # 1;
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+ # } else {
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+ # n * factorial(n - 1);
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+ # }
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+ # }
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+ # factorial(5);
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+ it 'evaluates recursive functions' do
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+ env = Environment.new
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+ AST::FunctionDefinition.new(
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+ AST::Identifier.new('factorial'),
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+ [AST::Identifier.new('n')],
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+ AST::Block.new([
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+ AST::Conditional.new(
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+ [
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+ AST::Branch.new(
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+ AST::Binary.new(
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+ AST::Operators::DOUBLE_EQUALS,
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+ AST::Identifier.new('n'),
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+ AST::Number.new(0.0),
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+ ),
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+ AST::Block.new([
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+ AST::Number.new(1.0),
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+ ])
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+ ),
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+ AST::Branch.new(
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+ AST::Boolean.new(true),
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+ AST::Block.new([
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+ AST::Binary.new(
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+ AST::Operators::MULTIPLY,
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+ AST::Identifier.new('n'),
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+ AST::FunctionCall.new(
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+ AST::Identifier.new('factorial'),
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+ [
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+ AST::Binary.new(
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+ AST::Operators::SUBTRACT,
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+ AST::Identifier.new('n'),
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+ AST::Number.new(1.0),
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+ )
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+ ]
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+ )
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+ )
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+ ])
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+ ),
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+ ]
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+ )
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+ ])
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+ ).execute(env)
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+ expect(
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+ AST::FunctionCall.new(
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+ AST::Identifier.new('factorial'),
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+ [AST::Number.new(5.0)]
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+ ).execute(env)
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+ ).to eq(120.0)
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+ end
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89
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+end
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