Class: BSV::Script::Interpreter

Inherits:
Object
  • Object
show all
Includes:
Operations::Arithmetic, Operations::Bitwise, Operations::Crypto, Operations::DataPush, Operations::FlowControl, Operations::Splice, Operations::StackOps
Defined in:
lib/bsv/script/interpreter/interpreter.rb,
lib/bsv/script/interpreter/operations/crypto.rb,
lib/bsv/script/interpreter/operations/splice.rb,
lib/bsv/script/interpreter/operations/bitwise.rb,
lib/bsv/script/interpreter/operations/data_push.rb,
lib/bsv/script/interpreter/operations/stack_ops.rb,
lib/bsv/script/interpreter/operations/arithmetic.rb,
lib/bsv/script/interpreter/operations/flow_control.rb

Overview

Bitcoin script interpreter implementing the post-Genesis BSV script engine.

Evaluates unlock + lock script pairs, supporting the full BSV opcode set including restored opcodes (OP_MUL, OP_LSHIFT, OP_CAT, etc.) and post-Genesis rules (OP_RETURN as early success, no script size limits).

Examples:

Evaluate scripts without transaction context

BSV::Script::Interpreter.evaluate(unlock_script, lock_script)

Verify a transaction input

BSV::Script::Interpreter.verify(
  tx: transaction, input_index: 0,
  unlock_script: input.script, lock_script: prev_output.script,
  satoshis: prev_output.satoshis
)

Defined Under Namespace

Modules: Operations

Constant Summary collapse

CONDITIONAL_OPCODES =

Conditional opcodes must be processed even in non-executing branches to maintain correct nesting depth. OP_VERIF and OP_VERNOTIF are included here because they open conditional blocks (like OP_IF/OP_NOTIF) and must be dispatched to track nesting depth even when the branch is not executing. This matches the Go SDK’s IsConditional() function.

[
  Opcodes::OP_IF, Opcodes::OP_NOTIF, Opcodes::OP_ELSE, Opcodes::OP_ENDIF,
  Opcodes::OP_VERIF, Opcodes::OP_VERNOTIF
].freeze
MAX_CONDITIONAL_DEPTH =

Maximum nesting depth for OP_IF / OP_NOTIF blocks. Prevents interpreter stack overflow from deeply nested conditionals.

256

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#astack ⇒ Object (readonly)

Returns the value of attribute astack.



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# File 'lib/bsv/script/interpreter/interpreter.rb', line 40

def astack
  @astack
end

#dstack ⇒ Object (readonly)

Returns the value of attribute dstack.



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# File 'lib/bsv/script/interpreter/interpreter.rb', line 40

def dstack
  @dstack
end

Class Method Details

.evaluate(unlock_script, lock_script) ⇒ Boolean

Evaluate unlock + lock scripts without transaction context.

Signature operations will always fail (no sighash available).

Parameters:

  • unlock_script (Script) —

    the unlocking script

  • lock_script (Script) —

    the locking script

Returns:

  • (Boolean) —

    true if execution succeeds

Raises:



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# File 'lib/bsv/script/interpreter/interpreter.rb', line 64

def self.evaluate(unlock_script, lock_script)
  new(
    unlock_script: unlock_script,
    lock_script: lock_script
  ).execute
end

.verify(tx:, input_index:, unlock_script:, lock_script:, satoshis:) ⇒ Boolean

Verify a transaction input by evaluating its scripts.

Parameters:

  • tx (Transaction::Transaction) —

    the transaction being verified

  • input_index (Integer) —

    the input index within the transaction

  • unlock_script (Script) —

    the input’s unlocking script

  • lock_script (Script) —

    the previous output’s locking script

  • satoshis (Integer) —

    the value of the previous output in satoshis

Returns:

  • (Boolean) —

    true if verification succeeds

Raises:



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# File 'lib/bsv/script/interpreter/interpreter.rb', line 80

def self.verify(tx:, input_index:, unlock_script:, lock_script:, satoshis:)
  new(
    unlock_script: unlock_script,
    lock_script: lock_script,
    tx: tx,
    input_index: input_index,
    satoshis: satoshis
  ).execute
end

Instance Method Details

#execute ⇒ Object 



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# File 'lib/bsv/script/interpreter/interpreter.rb', line 90

def execute
  scripts = [@unlock_script, @lock_script]

  scripts.each_with_index do |script, script_idx|
    @current_script = script
    chunks = script.chunks

    chunks.each_with_index do |chunk, chunk_idx|
      @current_chunk_idx = chunk_idx
      execute_opcode(chunk)
      break if @early_return
    end

    break if @early_return && script_idx == 1

    # Between scripts: verify conditionals balanced
    raise ScriptError.new(ScriptErrorCode::UNBALANCED_CONDITIONAL, 'unbalanced conditional') unless @cond_stack.empty?

    # Clear alt stack between scripts
    @astack.clear

    # Reset state for next script
    @last_code_sep = 0
    @early_return = false
    @after_op_return = false
  end

  check_final_stack
  true
end