Error Catalog ============= Diagnostics ----------- Every diagnostic has the form:: [Error type], pos [line/col]: [message] for example:: Compile error, pos 5/1: resource capacity must be a non-negative integer; got -1 Positions are 1-indexed for both line and column. Runtime errors carry no position, because the failing instruction's source location is not retained by the VM:: Runtime error: integer division by zero Phases ------ An error belongs to exactly one phase, and the compiler stops at the end of the phase that produced it. A phase reports every independent fault it finds before stopping, so a file with two bad declarations yields two diagnostics rather than one; faults that are consequences of an earlier one in the same construct are suppressed: ============ ================================================== ``SCANNER`` Lexical: illegal characters, malformed literals, unterminated strings. ``PARSER`` Syntactic: a token stream that no production accepts, including reserved words used as identifiers. ``SEMANTIC`` Everything the grammar cannot express: types, scoping, effect discipline, declaration order, and the constraints in ``eb-constraints.rst``. ``RUNTIME`` Detected during execution: division by zero, out-of-range group index, a negative value where only a constant could have been checked earlier. ============ ================================================== Scanner and parser errors are reported one at a time. A semantic error does not stop analysis of unrelated declarations, so a single ``eb check`` may report several. Exit codes ---------- ===== =========================================== ``0`` success ``1`` runtime error ``2`` compile error (scanner, parser, or semantic) ===== =========================================== Constant versus runtime detection --------------------------------- Several rules are checked at compile time when the offending expression is a constant and at runtime otherwise — a negative ``timeout`` (AG-80), a negative ``sched`` delta (SCHED-15), a negative resource capacity (RC-30). The same violation therefore appears in this catalog under two different phases depending on how it was written. This is deliberate: constant-folding the check is an optimization, not a change in what is legal. The catalog ----------- What follows is generated from ``tests/suite`` by ``./mk errors`` and verified by ``./mk spec``. It is not maintained by hand: the test suite is what pins the behavior, so a hand-copied catalog could only drift from it. To add an entry, add a test case. Each entry gives the feature under test, the file it lives in, and the exact message the compiler is asserted to produce. .. BEGIN GENERATED CATALOG -- edit tests/suite, then run ./mk errors Scanner Errors -------------- 10 cases, from ``tests/suite/invalid_scanner/``. Every message below is the exact ``EXPECT-MSG`` the compiler is asserted to produce. **Illegal character** — ``at_sign.eb`` :: Scanner error, pos 5/6: illegal character '@' **Illegal character backtick** — ``backtick.eb`` :: Scanner error, pos 5/6: illegal character '`' **Invalid escape sequence** — ``bad_escape.eb`` :: Scanner error, pos 5/8: invalid escape sequence '\q' **Number literal — decimal point requires leading digit** — ``dbl_no_leading_digit.eb`` :: Scanner error, pos 5/6: number literal must have digit before decimal point **Number literal — digits required after decimal point** — ``dbl_no_trailing_digit.eb`` :: Scanner error, pos 5/6: number literal must have digit after decimal point **Illegal character $** — ``dollar_sign.eb`` :: Scanner error, pos 5/6: illegal character '$' **Multiple decimal points** — ``multiple_dots.eb`` :: Scanner error, pos 5/6: unexpected character in number literal **Digit run immediately followed by identifier character** — ``number_then_letter.eb`` :: Scanner error, pos 5/6: unexpected character in number literal **Trailing underscore in a number literal** — ``trailing_underscore.eb`` :: Scanner error, pos 5/6: unexpected character in number literal **Unterminated string literal** — ``unterminated_string.eb`` :: Scanner error, pos 5/6: unterminated string literal Parser Errors ------------- 14 cases, from ``tests/suite/invalid_parser/``. Every message below is the exact ``EXPECT-MSG`` the compiler is asserted to produce. **fn return type is mandatory** — ``fn_missing_ret.eb`` :: Compile error, pos 6/3: function return type is mandatory: expected ':' after ')' **Guard arm missing expression after ->** — ``guard_missing_expr.eb`` :: Compile error, pos 7/1: expected expression after '->' **init block requires end** — ``init_missing_end.eb`` :: Compile error, pos 8/1: expected 'end' to close 'init' block **Declaration missing right-hand side** — ``missing_rhs.eb`` :: Compile error, pos 6/1: expected expression, found EOF **obs_r with no variable** — ``obs_missing_var.eb`` :: Compile error, pos 6/1: expected variable name after 'obs_r' **obs_r requires a variable name, not a reserved word** — ``reserved_word_obs_r.eb`` :: Compile error, pos 5/7: expected variable name after 'obs_r' **Reserved word used as identifier** — ``reserved_word_run.eb`` :: Compile error, pos 5/1: 'run' is a reserved word and cannot be used as an identifier **resource capacity type must be int** — ``resource_non_int_type.eb`` :: Compile error, pos 5/1: resource capacity type must be 'int' **rsc is only a parameter type** — ``rsc_as_var_type.eb`` :: Compile error, pos 5/5: type 'rsc' is only valid as a parameter type **run() requires braces around duration and nruns** — ``run_missing_braces.eb`` :: Compile error, pos 6/7: expected '{' after run() arguments **run() duration and nruns are comma separated** — ``run_missing_comma.eb`` :: Compile error, pos 6/10: expected ',' between duration and nruns **timeout is not a valid pi body item** — ``timeout_in_pi.eb`` :: Compile error, pos 6/3: expected expression, found 'timeout' **timeout requires parentheses** — ``timeout_missing_parens.eb`` :: Compile error, pos 7/1: expected '(' after 'timeout' **Type keywords are lowercase only** — ``type_wrong_case.eb`` :: Compile error, pos 5/4: unknown type 'INT'; expected int, dbl, str, or bool Semantic Errors --------------- 30 cases, from ``tests/suite/invalid_semantic/``. Every message below is the exact ``EXPECT-MSG`` the compiler is asserted to produce. **Agent invocation is a statement, not an expression** — ``agent_in_expression.eb`` :: Compile error, pos 9/6: 'worker' is an agent and cannot be used in an expression **agent declared but no run()** — ``agent_no_run.eb`` :: Compile error: model has agent declarations but no run() statement **dbl value cannot be assigned to an int variable** — ``assign_dbl_to_int.eb`` :: Compile error, pos 5/10: cannot assign dbl to int variable 'x' **Assignment to an undeclared variable** — ``assign_without_decl.eb`` :: Compile error, pos 5/1: assignment to undeclared variable 'x'; use ':=' to declare **claim is invalid inside an event body** — ``claim_in_event.eb`` :: Compile error, pos 7/3: 'claim' is only valid inside an agent body or init block **claim argument must be type rsc** — ``claim_not_rsc.eb`` :: Compile error, pos 7/9: argument to 'claim' must be type rsc **fn body may not reference a pi by name** — ``fn_reads_pi.eb`` :: Compile error, pos 7/10: a function body may not reference pi 'x'; pass its value as a parameter (FN-35) **for loop variable may not shadow an outer variable** — ``for_shadow_outer.eb`` :: Compile error, pos 7/5: 'i' is already declared **Guard arms must produce the same type** — ``guard_arm_types.eb`` :: Compile error, pos 6/6: guard arms produce different types: int and str (GUARD-40) **Guard expression requires a terminating default arm** — ``guard_no_default.eb`` :: Compile error, pos 6/6: guard expression requires a terminating '_' (or 'true') arm **if condition must be bool** — ``if_cond_not_bool.eb`` :: Compile error, pos 7/4: if condition must be bool, got int **Series extraction on a non-observed variable** — ``last_not_observed.eb`` :: Compile error, pos 7/12: ':last' requires observation data; 'y' is not observed **Simulation model requires observations** — ``model_no_obs.eb`` :: Compile error: there are no observations in the model **No-horizon pi model without stop_r or halt** — ``no_horizon_no_stop.eb`` :: Compile error: a run with no time horizon requires a stop_r or halt **pi and obs declared but no run()** — ``pi_no_run.eb`` :: Compile error: model has pi declarations but no run() statement **More than one :randseed call is invalid** — ``randseed_twice.eb`` :: Compile error: more than one ':randseed' call is not permitted (EXEC-35) **Constant resource capacity below zero** — ``rc_capacity_negative.eb`` :: Compile error, pos 5/1: resource capacity must be a non-negative integer; got -1 **Redeclaration of an already-declared variable** — ``redeclare_var.eb`` :: Compile error, pos 6/1: 'x' is already declared **release is invalid inside an event body** — ``release_in_event.eb`` :: Compile error, pos 9/3: 'release' is only valid inside an agent body or init block **release argument must be type rsc** — ``release_not_rsc.eb`` :: Compile error, pos 9/11: argument to 'release' must be type rsc **run() requires a simulation declaration** — ``run_with_no_sim.eb`` :: Compile error: run() requires at least one pi, event, or agent declaration **Only event handlers may be scheduled** — ``sched_a_fn.eb`` :: Compile error, pos 9/10: 'f' is a fn; only event handlers may be scheduled **Shadowing a module-level declaration is prohibited** — ``shadow_module_var.eb`` :: Compile error, pos 7/3: declaration of 'x' shadows a module-level declaration **stop_r at model level is invalid** — ``stop_r_model_level.eb`` :: Compile error, pos 7/1: 'stop_r' is only valid inside pi, event, agent, or init bodies **stop_s inside an event body is invalid** — ``stop_s_in_event.eb`` :: Compile error, pos 6/3: 'stop_s' is only valid at module level **timeout is invalid inside an event body** — ``timeout_in_event.eb`` :: Compile error, pos 6/3: 'timeout' is only valid inside an agent body or init block **timeout is invalid inside a fn body** — ``timeout_in_fn.eb`` :: Compile error, pos 6/3: 'timeout' is only valid inside an agent body or init block **Constant negative timeout delta** — ``timeout_negative_const.eb`` :: Compile error, pos 6/3: 'timeout' delta must be non-negative; got -1 **Only one init block per program** — ``two_init_blocks.eb`` :: Compile error: only one 'init' block is permitted per program **Reference to an undefined variable** — ``undefined_var.eb`` :: Compile error, pos 5/6: undefined variable 'x' Runtime Errors -------------- 6 cases, from ``tests/suite/invalid_runtime/``. Every message below is the exact ``EXPECT-MSG`` the compiler is asserted to produce. **Runtime group index out of declared range** — ``grp_index_out_of_range.eb`` :: Runtime error: group index 4 is out of range 1..3 **Integer division by zero** — ``int_div_zero.eb`` :: Runtime error: integer division by zero **:nth index out of range at runtime** — ``nth_out_of_range.eb`` :: Runtime error: ':nth' index 6 is out of range 1..5 **double release — the second finds nothing held** — ``release_twice.eb`` :: Runtime error: release of resource 'r', which this agent does not hold **releasing a resource the agent does not hold** — ``release_without_claim.eb`` :: Runtime error: release of resource 'r', which this agent does not hold **Negative timeout delta at runtime** — ``timeout_negative_runtime.eb`` :: Runtime error: 'timeout' delta must be non-negative .. END GENERATED CATALOG