Compile Time Abstraction Techniques for the D Programming Language

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Compile Time Abstraction Techniques for the D
Programming Language

• Benjamin Shropshire

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Abstraction

• What
• Why
• When
• How

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What Why

• What Isolation of lower level complexity
• Distillation of Intent
• Removal of redundancy
• Why Saving Time
• Programming time
• Maintenance time
• User time

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When to use Abstractions?

• Let the computer do what it is good at.
• Abstract where abstraction is a good fit

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When to Not use Abstractions?

• If the abstraction doesn't fit, don't force it.
• Beware of premature optimizations.
• Code speed
• Coding speed
• Test optimizations.

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Compile time processing

• Nesting Templates
• Chained Recursion
• Nested Tuples

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Nesting Templates
Define two lists using two templates
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Nesting Templates

• Multiple Tuples
• Useful naming

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Chained Recursion
Starting point Introduce alias to nested
templates Nested templates that do something and
then also use mixin
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Chained Recursion

• Object Oriented style design
• Domain Specific Languages
• Closer to what is wanted

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Nested Tuples
Alias tuples inside of strut
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Nested Tuples

• Use structs
• Alias in templates dont work
• foreach works well on types

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All Together Now

• Compile Time Parsing
• Compile Time Parser Generation

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Compile Time Parsing

• Reading Data
• Building tree

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Compile Time Parsing
Attempt to parse D
Attempt to parse B
Build tuple of Ds Record unused input
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Compile Time Parsing
Found BCA
Found BC failed on A, so parsing only B
Found B failed on C, so parsing only B
Failed on B, so failing
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Compile Time Parsing
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Compile Time Parser Generation

• Parse grammar
• Select production to instance
• Try each disjunction
• Try each part
• Recurs to other productions
• Record checkpoints
• Backtrack through checkpoints on failure

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Compile Time Parser Generation
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Compile Time Abstraction Techniques for the D
Programming Language Benjamin Shropshire
Special Thanks to

• Dr. Robert Hiromoto
• Michael Hewitt

• Dr. David Buehler
• Dr. Geoffrey Shropshire
• Eric Hewitt