Skip to content

14_error_codes.md

Latest commit

 

History

History
271 lines (196 loc) · 16 KB

14_error_codes.md

File metadata and controls

271 lines (196 loc) · 16 KB
Raw

14 — TechScript 2.0 Error Code Specification

Status: Authoritative Specification Version: 2.0.0 Last Updated: 2026-07-26

Table of Contents

  1. Error Code Namespaces
  2. Lexer Errors — TSE0001–TSE0099
  3. Parser Errors — TSE0100–TSE0299
  4. Semantic Errors — TSE0300–TSE0499
  5. DSL Validation Errors — TSE0400–TSE0499
  6. Runtime Errors — TSE1000–TSE1999
  7. Deprecation Warnings — Parser Phase — TSW1001–TSW1099
  8. Style / Lint Warnings — Semantic Phase — TSW2001–TSW2099
  9. Informational Hints — TSI3001–TSI3099
  10. Migration

Error Code Namespaces

All diagnostic codes follow the pattern <prefix><4-digit-code>. The prefix encodes both the severity and the compiler phase that emits the diagnostic.

Prefix Range Severity Phase Description
TSE0xxx 0001 – 0999 Error Compile-time Hard errors that halt compilation
TSE1xxx 1000 – 1999 Error Runtime Errors raised during execution
TSW1xxx 1001 – 1099 Warning Parser Deprecated syntax warnings
TSW2xxx 2001 – 2099 Warning Semantic / Lint Style and semantic lint warnings
TSI3xxx 3001 – 3099 Hint / Info Semantic Non-blocking improvement hints

Note: Errors (TSE) always halt the current compilation unit. Warnings (TSW) and hints (TSI) are emitted as diagnostics but do not prevent output generation unless --strict mode is enabled.

Lexer Errors — TSE0001–TSE0099

Lexer errors occur during tokenisation, before any parsing takes place.

Code Message Cause Example
E0001 Unexpected character A character that is not part of the TechScript 2.0 grammar was found x = @5
E0010 Trailing underscore in number A numeric literal ends with an underscore separator 1_000_
E0011 Empty numeric prefix A base prefix (0x, 0b, 0o) is not followed by any digit 0x
E0012 Invalid base digit A digit does not belong to the declared numeric base 0b102
E0021 Unterminated string A string literal is opened but never closed before end-of-line or end-of-file x = "hello

Diagnostic Format

[TSE0001] file.ts:3:8 — Unexpected character '@'
         x = @5
             ^

Parser Errors — TSE0100–TSE0299

Parser errors occur when the token stream does not conform to the TechScript 2.0 grammar.

Code Message Cause
E0100 Expected expression A position that requires an expression received a non-expression token
E0101 Expected identifier A position that requires a name (variable, function, class) received another token
E0104 Expected end to close block A block was opened (by do, when, repeat, for, class, etc.) but end was not found before the next top-level token
E0105 Expected block body A block-introducing keyword was not followed by an indented body
E0107 Expected statement terminator (missing newline) Two statements appear on the same line without a valid separator
E0113 Invalid assignment target The left-hand side of = is not a valid l-value (e.g., a literal or expression)

E0104 Detail

TechScript 2.0 uses indentation and the end keyword to delimit blocks. Curly-brace ({ / }) delimiters are not part of the language. This error fires when the parser expects end but encounters something else.

Incorrect (deprecated brace style):

do greet(name)
{
    say $"Hello {name}"
}

Correct (canonical 2.0):

do greet(name)
    say $"Hello {name}"
end

Semantic Errors — TSE0300–TSE0499

Semantic errors are detected after parsing, during name resolution and type analysis.

Name & Scope Errors

Code Message Cause
E0300 Undefined variable <name> A name is referenced that has not been declared in any accessible scope
E0301 Duplicate declaration <name> in scope A name is declared more than once in the same scope level
E0302 Cannot reassign const <name> An assignment targets a name declared with const
E0303 Variable <name> used before assignment A variable is read before it has been given a value

Call & Signature Errors

Code Message Cause
E0310 Wrong argument count: too few for <name> A function call provides fewer arguments than the function requires
E0311 Wrong argument count: too many for <name> A function call provides more arguments than the function accepts

Control-Flow Errors

Code Message Cause
E0312 send outside function body A send statement appears at module/top level, outside any do block
E0313 Mixed top-level statements with explicit main Top-level executable statements exist alongside an explicitly declared main function
E0320 self used outside method The implicit self reference appears in a function that is not a class method

Module Errors

Code Message Cause
E0340 Module not found: <path> A use statement names a module that cannot be resolved
E0350 Cannot export non-exportable declaration An export modifier is applied to a declaration that is not allowed to be exported (e.g., a local variable)

DSL Validation Errors — TSE0400–TSE0499

DSL validation errors are raised when embedded domain-specific language blocks fail structural validation.

Code Message Cause
E0400 DSL block missing required field <field> A mandatory field is absent from a DSL block definition
E0401 DSL field <field> has wrong type A DSL field value does not match the expected type for that field
E0402 Unknown DSL directive <directive> An unrecognised directive keyword appears inside a DSL block
E0403 DSL block nesting depth exceeded A DSL block is nested beyond the maximum allowed depth

Runtime Errors — TSE1000–TSE1999

Runtime errors are raised by the TechScript 2.0 virtual machine during program execution. They may be caught with try / catch unless marked uncatchable.

Code Message Catchable Cause
E1010 Division by zero ✅ An integer or float division or modulo operation with a zero divisor
E1011 Type mismatch ✅ An operation received a value of an incompatible type
E1020 Stack overflow ❌ Unbounded or excessively deep recursion exhausted the call stack
E1030 Value not iterable in for loop ✅ The target of for x in y is not a sequence, range, or iterator
E1041 Field or method <name> not found ✅ A field access or method call targets a name that does not exist on the object
E1050 Index out of bounds ✅ A list or string subscript is outside the valid index range

Catching Runtime Errors

try
    result = items[idx]
catch e
    say $"Caught: {e.code} — {e.message}"
end

Deprecation Warnings — Parser Phase — TSW1001–TSW1099

These warnings are emitted when the parser encounters syntax from TechScript 1.x that has been superseded in 2.0. The code will still compile, but the deprecated form should be migrated to its canonical replacement.

Code Deprecated Syntax Canonical Replacement (2.0)
TSW1001 make x = 5, let x = 5, var x = 5 Plain assignment: x = 5
TSW1002 build fn(), fun fn(), function fn() do fn()
TSW1003 return x send x
TSW1004 attempt { … } try … end
TSW1005 give x send x
TSW1006 { } block delimiters, ; statement terminators end, newlines
TSW1007 if cond, elif cond when cond, else when cond
TSW1008 while cond repeat cond
TSW1009 import mod, from mod import x use mod
TSW1010 each x in y for x in y
TSW1011 none null
TSW1012 f"…" f-strings $"…" interpolated strings
TSW1013 model Name class Name
TSW1014 std.io.println(x) Built-in say x

Example Warning Output

[TSW1002] file.ts:12:1 — Deprecated: 'build' is a TechScript 1.x keyword.
  Use 'do' for function declarations.
  12 | build greet(name)
       ^^^^^
  Canonical: do greet(name)
  Run: tsc migrate file.ts  to apply automatic fix.

Style / Lint Warnings — Semantic Phase — TSW2001–TSW2099

Lint warnings are raised by the semantic analyser to flag code that is syntactically valid but stylistically problematic or potentially erroneous.

Code Message Cause
TSW2001 Variable <name> declared but never used A variable is assigned a value that is never subsequently read
TSW2002 Variable <name> shadows outer scope A declaration in an inner scope has the same name as one in an outer scope, hiding the outer binding

Informational Hints — TSI3001–TSI3099

Hints are purely informational suggestions. They do not indicate incorrect code; they point toward idiomatic TechScript 2.0 style. Hints are suppressed by default and enabled with --hints or in editor integrations.

Code Message
TSI3001 Consider using $"…" string interpolation instead of string concatenation with +

Example

# Triggers TSI3001
greeting = "Hello, " + name + "!"

# Idiomatic 2.0
greeting = $"Hello, {name}!"

Migration

Automatic Migration Tool

Run the following command to automatically rewrite all TSW1001–TSW1013 deprecated-syntax patterns to their canonical 2.0 equivalents:

tsc migrate <file-or-directory>

The migrator performs in-place rewrites with a .bak backup of the original. After migration, re-run the compiler to confirm that no warnings remain.

Manual Mapping Reference

For manual migration, use the Deprecation Warnings table above as a find-and-replace reference. The most common migrations are:

Pattern Replace with
build / fun / function do
return send
if / elif when / else when
while repeat
import / from … import use
none null
f"…" $"…"
model class
{ … } block delimiters indent + end
; statement terminators newline

Note: TSW1014 (std.io.println → say) is excluded from automatic migration because the migrator cannot always distinguish qualified std.io.println calls from user-defined functions with the same name. Verify these manually.

End of specification — TechScript 2.0 Error Code Reference v2.0.0