sysl 0.0.154 — a comparison missing its right operand says 'expression expected'

A comparison with nothing usable on its right now says expression expected instead of telling you about a range you never wrote. Nothing else changes in how programs compile.

Behaviour changes

None. Every program that compiled on 0.0.153 compiles to the same thing on 0.0.154, and every program it refused is still refused. The one change is the wording and the reason of one parse error (below); its position is the same as before.

Fixes

A comparison missing its right operand says expression expected, not '..' expected

Before: when the right side of a comparison was missing, or was something that cannot be an operand, the parser reported the range operator:

val c = true
var z = 1 < if c then 1 else 2

error: '..' expected
  --> main.sysl:2:13

print(1 < ) got the same message, as did every other comparison operator (==, !=, <=, >=, >) and the second link of a chain (print(1 < 2 < )). No range was involved. A comparison's operand is parsed as a range expression, and the last thing that rule tries is a bare ... Every alternative failed at the same token, the last failure won the tie, and so the message named the range.

Now the same position gets error: expression expected. The range rule is labelled as an expression, the same way the unary rule already was, so a failure at its first token names what was missing. Parse results do not change. The range's own refusal, '..=' is not a range — inclusive is 'a..b' and exclusive is 'a..<b', is still reported as before. (99e0306)

Tests

• ParseDiagnosticTests § a comparison with no value on its right wants a value, not a range: 4 new cases.
  • Nothing after the operator: print(1 < ) at 1:11.
  • An if as the right operand at 2:13.
  • All six comparison operators, plus the second link of a chain at 1:15.
  • The ..= refusal still naming the range.
• ArcCodegenTests "a field through a reference reaches past the header" used to match the weak-count store at header slot 2. It now asserts the real field access: a GEP into slot 3 (the payload), the GEP for y within it, and the store i32 9 landing on that address. (0acf71a)

Documentation

• The README now says sysl is not published to Maven Central and points to GitHub Packages, where the jars are. (ef803a9)
• No page on sysl.sh quoted the old '..' expected refusal, so the site needed only the version pin.

Install

brew install sysl-lang/tap/sysl      # or: brew upgrade sysl

The tarballs for macOS arm64, Linux x86_64 and Linux arm64 are attached to this release. The sh.sysl:sysl_3:0.0.154 jars are on GitHub Packages (https://maven.pkg.github.com/sysl-lang/sysl-bootstrap). As of 0.0.153, sysl is not published to Maven Central.

Verification

• Native gate on the tagged tree (80c8695): GREEN, 12,282 succeeded and 0 failed. That is 416 suites: 6 ran alone and 410 in 46 chunks. Nothing timed out and nothing was retried. The gate covers syslNative and syslDocNative. It took 51:58, after a cleaned warnings census.
• Warnings census, cleaned: JVM two, JS three, Native three, syslDocJVM one, syslDocNative two. That is the expected count, and every warning belongs to a dependency or is build infrastructure.
• Release tarball: extracted to a scratch prefix and run. sysl --version prints sysl 0.0.154, sysl-doc is present, and the comparison above reports expression expected at 2:13.
• brew: brew test sysl passes, and the installed sysl --version prints sysl 0.0.154. The Linux glibc floor, measured in the release run, is 2.34.
• sysl.sh on 0.0.154: 1,415 tests pass with 0 failures. Of those, 1,395 are DocsTests.
• Org sweep with the release tarball's own binary: 74 builds, 74 green.
  • 54 ran under sysl test ., 12 under sysl build . and 5 under sysl build-c <dir>.
  • Three repos fail the bare command by design and were run as their READMEs say. freertos against a freshly built FreeRTOS-Kernel POSIX port: 84 passed. libpq against a scratch PostgreSQL: 51 passed. quickjs-ng with its include path: 33 passed.
  • pico: build-lib --target thumbv6m-freestanding gets as far as the pico-sdk's generated cyw43_arch.h, which means the sysl type-check passed.
  • Not swept, being kernel or board repos that need a toolchain or SDK this machine does not have: pico2, zephyr, picokit, ogol-pico, ogol-pico2, solder-pico2, zephyr-demo, pico-scratch. Also not swept, being infrastructure: sysl-bootstrap, sysl (the self-hosted compiler), sysl.sh, homebrew-tap, github-profile and svd.