mirror of
https://github.com/samsonjs/csc360-a1-shell.git
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Sami Samhuri
4f4e97475b
Replace Ruby's old wordexp-like command splitting with a tokenizer and
parser that understands ; and && while honoring quotes and nesting.
Implement richer expansions for command substitution, arithmetic,
parameter defaults (${var:-...}), brace expansion, and escaped
dollar/backtick behavior via shared quote-state handling.
Expand the test suite with parser/expansion edge cases, escaping
parity checks, builtin usage validation, and job-control refresh tests.
Keep C green by adding a compat test profile for c/Makefile test and
by returning nonzero on builtin failures in -c mode, including clearer
`bg` usage output.
64 lines
1.4 KiB
Ruby
64 lines
1.4 KiB
Ruby
module Shell
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# Shared quote/escape state machine for parsers that walk shell-like strings.
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class QuoteCursor
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attr_reader :state
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def initialize(state: :unquoted)
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@state = state
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end
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def unquoted?
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state == :unquoted
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end
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# Consumes one logical unit from line[index], which may be one character
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# or an escape pair (e.g., \" or \\$), and updates internal quote state.
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# Returns [segment, next_index].
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def consume(line, index)
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c = line[index]
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case state
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when :unquoted
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consume_unquoted(line, index, c)
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when :single_quoted
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consume_single_quoted(index, c)
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when :double_quoted
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consume_double_quoted(line, index, c)
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else
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raise "Unknown state #{state}"
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end
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end
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private
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def consume_unquoted(line, index, c)
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case c
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when "'"
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@state = :single_quoted
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when "\""
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@state = :double_quoted
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when "\\"
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if index + 1 < line.length
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return [line[index, 2], index + 2]
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end
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end
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[c, index + 1]
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end
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def consume_single_quoted(index, c)
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@state = :unquoted if c == "'"
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[c, index + 1]
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end
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def consume_double_quoted(line, index, c)
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if c == "\\"
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if index + 1 < line.length
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return [line[index, 2], index + 2]
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end
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elsif c == "\""
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@state = :unquoted
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end
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[c, index + 1]
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end
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end
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end
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