chen_lang

A tiny programming language written in Rust

🇨🇳 中文版

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Sample Code

# This is a comment 
# Comments start with #, and go to the end of the line
# The expressions in if and for evaluate to bool
let i=1
for i<=9 {
    let j = 1
    for j<=i {
        print(j + "x" + i + "=" + i*j + " ")
        j = j + 1
    }
    println("")
    i=i+1
}

Output:

1x1=1  
1x2=2 2x2=4
1x3=3 2x3=6 3x3=9
1x4=4 2x4=8 3x4=12 4x4=16
1x5=5 2x5=10 3x5=15 4x5=20 5x5=25
1x6=6 2x6=12 3x6=18 4x6=24 5x6=30 6x6=36
1x7=7 2x7=14 3x7=21 4x7=28 5x7=35 6x7=42 7x7=49
1x8=8 2x8=16 3x8=24 4x8=32 5x8=40 6x8=48 7x8=56 8x8=64  
1x9=9 2x9=18 3x9=27 4x9=36 5x9=45 6x9=54 7x9=63 8x9=72 9x9=81

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let i = 100
let sum = 0 
for i!=0 {
    i = i - 1
    # Here is relatively complex logical operation
    if (i%2!=0) || (i%3==0) {
        # println(i)
        # Uncomment the line above
        # Print out all odd numbers or even numbers divisible by 3
        sum = sum + i
    }
}
println("The sum of odd numbers or even numbers divisible by 3 below 100 is")  
println(sum)

Output:

The sum of odd numbers or even numbers divisible by 3 below 100 is
3316

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# Use chen_lang to print the first 30 Fibonacci numbers 
let n = 1
let i = 1
let j = 2
println("Print the first 10 Fibonacci numbers")
for n <= 30 {
   println(i)
   let tmp = i
   i = j
   j = tmp + j
   n = n + 1 
}

Output:

Print the first 10 Fibonacci numbers
1
2
3  
5
8
13
21
34
55
89

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TODO

• if condition statements
• else statements
• for loops
• Support break and continue keywords
• bool type
• int type
• Arithmetic operators + - * / %
• Comparison operators > >= < <= == !=
• Logical operators && || !
• Operator precedence
• Operator precedence can be changed dynamically with parentheses
• Custom methods
• More code comments
• Write blog to document this project
• More comprehensive unit tests
• Object oriented features

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Afterword: I finally implemented a program I've always wanted to write, thanks to the compiler principles course at Harbin Institute of Technology.