<external identifier> ::= <identifier>
<external list> ::= <external identifier>
| <external identifier>, <external list>
<external declaration> ::= external <external list>
| <type> external <external list>
APPENDIX B
Hardware Representation
One keypunch character is reserved as an “escape symbol”, which we shall here suppose is the apostrophe. This symbol is used to delineate word delimiters and truth values, which are written in boldface type in Algol reference language and publication language and indicated by underlining in this manual. The hardware representation of a word delimiter such as begin is therefore 'BEGIN'. No distinction is made between upper and lower case letters in the hardware language.
The transliteration rules for the non-word delimiters are comprised in the following table. This assumes a 48 character hardware set and is consistent with the usage in the ALCOR group. For some basic symbols alternatives are tolerated, as indicated.
| Reference | Hardware | Tolerated Hardware |
|---|---|---|
| < | 'LS' | 'LESS' |
| ≤ | 'LQ' | 'LSEQ', 'NOTGREATER', 'NOT GREATER' |
| = | 'EQ' | 'EQUAL' |
| ≥ | 'GQ' | 'GREQ', 'NOTLESS', 'NOT LESS' |
| > | 'GR' | 'GREATER' |
| ≠ | 'NQ' | 'NTEQ', 'NOTEQUAL', 'NOT EQUAL' |
| ¬ | 'NOT' | |
| ∧ | 'AND' | |
| ∨ | 'OR' | |
| ⊃ | 'IMP' | 'IMPLIES', 'IMPL' |
| ≡ | 'EQV' | 'EQUIV' |
| ₁₀ | ' | 'E','T' |
| × | * | |
| ↑ | ** | 'POWER' |
| ÷ | // | 'DIV' |
| : | .. | |
| ; | $ | ., |
| := | = | .=, ..= |
| [ | (/ | |
| ] | /) | |
| ‘ | " | '(' |
| ’ | " | ')' |
In the case of the string quotes, the tolerated symbols are required for the inner strings of a nest of strings.