Parser: add missing standard infix operators (** ^ >> << xor div /\ \/ :) #29

New issue

Closed

opened 2026-06-02 20:08:44 +00:00 by navicore · 1 comment

navicore commented

2026-06-02 20:08:44 +00:00

Owner

Summary

Several standard infix operators are absent from the parser. Tested via
in-file clauses (which error cleanly on an unknown operator):

Operator	Std type/prec	Role	Status
`**`	xfx 200	float power	parse error (`unexpected \`*``)
`^`	xfy 200	int power	parse error (`Unexpected character '^'`)
`>>`	yfx 400	shift right	parse error (`expected \`.`, got `>``)
`<<`	yfx 400	shift left	parse error
`xor`	yfx 500	bitwise xor	parse error (`got atom \`xor``)
`div`	yfx 400	floor division	parse error (`got atom \`div``)
`/\`	yfx 500	bitwise and	parse error (`Unexpected '\'`)
`\/`	yfx 500	bitwise or	parse error
`:`	xfy 200	module/qualifier	parse error (`Unexpected ':'`)

Supported today (baseline): mod, rem, + - * / //, the 700-level
comparison/is/=.. family, and , ; ->.

Repro

t :- X is 2 ** 3, X =:= 8.      % Parse error: unexpected `*`
t :- X is 8 >> 1, X =:= 4.      % Parse error: expected `.`, got `>`
t :- X is 6 /\ 3, X =:= 2.      % Parse error: Unexpected '\'

Notes

The arithmetic ones (** ^ >> << xor div /\ \/) need both a parser
operator entry and an evaluable-function in is/2.
: is non-arithmetic (module qualifier / general infix) — parser-level only.
Bitwise \ (and /\, \/) require tokenizer work — \ is not a standalone
token today (see prefix-gap issue #28).

Context

Found while building the loglings operator lessons. Companion to the prefix
gap (#28). Together these complete the standard operator table, after which the
"full prefix + infix" documentation can be written accurately.

Reported against prlg 0.4.1.

## Summary Several standard infix operators are absent from the parser. Tested via in-file clauses (which error cleanly on an unknown operator): | Operator | Std type/prec | Role | Status | |---|---|---|---| | `**` | xfx 200 | float power | parse error (`unexpected \`*\``) | | `^` | xfy 200 | int power | parse error (`Unexpected character '^'`) | | `>>` | yfx 400 | shift right | parse error (`expected \`.\`, got \`>\``) | | `<<` | yfx 400 | shift left | parse error | | `xor`| yfx 500 | bitwise xor | parse error (`got atom \`xor\``) | | `div`| yfx 400 | floor division | parse error (`got atom \`div\``) | | `/\` | yfx 500 | bitwise and | parse error (`Unexpected '\'`) | | `\/` | yfx 500 | bitwise or | parse error | | `:` | xfy 200 | module/qualifier | parse error (`Unexpected ':'`) | Supported today (baseline): `mod`, `rem`, `+ - * / //`, the 700-level comparison/`is`/`=..` family, and `, ; ->`. ## Repro ```prolog t :- X is 2 ** 3, X =:= 8. % Parse error: unexpected `*` t :- X is 8 >> 1, X =:= 4. % Parse error: expected `.`, got `>` t :- X is 6 /\ 3, X =:= 2. % Parse error: Unexpected '\' ``` ## Notes - The arithmetic ones (`** ^ >> << xor div /\ \/`) need **both** a parser operator entry **and** an evaluable-function in `is/2`. - `:` is non-arithmetic (module qualifier / general infix) — parser-level only. - Bitwise `\` (and `/\`, `\/`) require tokenizer work — `\` is not a standalone token today (see prefix-gap issue #28). ## Context Found while building the `loglings` operator lessons. Companion to the prefix gap (#28). Together these complete the standard operator table, after which the "full prefix + infix" documentation can be written accurately. --- Reported against `prlg` 0.4.1.

navicore referenced this issue

2026-06-02 20:09:28 +00:00

Docs: document operator support (full prefix + infix; postfix unsupported by design) #31

navicore referenced this issue from a commit

2026-06-02 22:52:54 +00:00

● Every operator works correctly. Issue #29 is implemented.

navicore referenced this issue

2026-06-02 22:53:18 +00:00

● Every operator works correctly. Issue #29 is implemented. #33

navicore commented

2026-06-02 22:53:34 +00:00

Author