Add optional gawk-style arrays of arrays (a[i][j])#439
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- Add allowArraysOfArrays to AwkSettings (default: true) - Thread the flag into Awk.compile() and Awk.compileExpression() - Update AwkParser to parse chained-bracket syntax a[i][j] when enabled - Introduce new opcodes for nested array lvalue operations - Extend AVM to execute nested-array tuples at runtime - Cover reads, writes, in, for-in, delete, ++/--, compound assignment - Add regression tests in AwkTest and AwkParserTest - Update documentation (README, compatibility.md, java.md, java-compile.md) Closes #438
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Pull request overview
Adds optional (default-enabled) support for gawk-style “arrays of arrays” syntax (a[i][j]) across the Jawk compiler and runtime, including parser acceptance, new tuple opcodes, and AVM execution, with accompanying regression and documentation updates.
Changes:
- Introduces
AwkSettings.allowArraysOfArraysand threads it into compilation so the parser can accept/reject chained-bracket syntax. - Extends
AwkParser, tuples/opcodes, andAVMto support nested-array reads/writes and array-valued operations on subarrays. - Expands test coverage (including parser-rejection when disabled) and updates site docs; enables additional POSIX conformance tests by implementing
length(array).
Reviewed changes
Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| src/main/java/io/jawk/util/AwkSettings.java | Adds allowArraysOfArrays compile-time flag and exposes it via API/diagnostics. |
| src/main/java/io/jawk/Awk.java | Passes allowArraysOfArrays into AwkParser during compilation/expression compilation. |
| src/main/java/io/jawk/frontend/AwkParser.java | Parses chained brackets when enabled; updates tuple generation to support subarrays in in, for-in, delete, assignment, built-ins, and function params. |
| src/main/java/io/jawk/intermediate/Opcode.java | Adds new opcodes to operate on stack-provided map elements and nested-array creation. |
| src/main/java/io/jawk/intermediate/AwkTuples.java | Adds tuple emission helpers for the new map-element opcodes. |
| src/main/java/io/jawk/backend/AVM.java | Implements execution for new opcodes; adds length(array) behavior and scalar/array context checks. |
| src/test/java/io/jawk/AwkTest.java | Adds behavior-based regression tests covering nested array semantics and key runtime paths. |
| src/test/java/io/jawk/AwkParserTest.java | Adds test ensuring chained-bracket syntax is rejected when allowArraysOfArrays is disabled. |
| src/test/java/io/jawk/PosixConformanceTest.java | Enables POSIX tests that rely on length(array) by removing prior assumptions. |
| src/site/markdown/java.md | Documents the new AwkSettings.setAllowArraysOfArrays(...) option and default behavior. |
| src/site/markdown/java-compile.md | Documents that compilation settings affect accepted syntax; shows disabling arrays-of-arrays before compiling. |
| src/site/markdown/compatibility.md | Notes support for arrays-of-arrays alongside classic SUBSEP multidimensional arrays. |
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jawk/src/main/java/io/jawk/frontend/AwkParser.java
Lines 4397 to 4400 in ff4cd66
Autovivify missing parent arrays on nested reads
This rvalue path dereferences nested arrays via getAst1().populateTuples()/dereferenceArray() without creating an intermediate subarray, so print a[1][2] on an unset a[1] ends up dereferencing a blank scalar as an array at runtime. That is inconsistent with the new gawk-style arrays-of-arrays behavior (and with this patch’s write-side autovivification), causing nested reads on previously unset parents to fail unexpectedly.
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Pull request overview
Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.
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Pull request overview
Copilot reviewed 12 out of 12 changed files in this pull request and generated 1 comment.
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Pull request overview
Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.
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Pull request overview
Copilot reviewed 12 out of 12 changed files in this pull request and generated 1 comment.
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Closes #438
Summary
This PR adds support for optional gawk-style arrays of arrays (
a[i][j]) as described in issue #438.Changes
AwkSettingsallowArraysOfArraysfield (default:true) to enable/disable chained-bracket syntax at compile time.AwkallowArraysOfArrayssetting intoAwkParserviacompile()andcompileExpression().AwkParserallowArraysOfArraysis enabled, parse chained-bracket expressions (a[i][j],a[i][j][k], mixed forms likea[i][j,k]) instead of throwing an error.SUBSEP(unchanged behavior).Opcode/AwkTuplesin,for-in,delete,++/--, and compound assignment on nested arrays.AVMMap-based infrastructure.Behavior
a[1][2] = 42; print a[1][2]42a[1][2,3] = 42; print a[1][2,3]SUBSEPa[1,2] = 42; print a[1,2]2 in a[1]for (k in a[1])delete a[1][2]allowArraysOfArrays = false+a[1][2]Tests
AwkTestcovering the acceptance criteria from the issue.AwkParserTestfor when the flag is disabled.Documentation
README.md,compatibility.md,java.md, andjava-compile.md.